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Glossary of terms used in health research - P

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  • P value
    • Wikipedia
      The probability (ranging from zero to one) that the results observed in a study (or results more extreme) could have occurred by chance if in reality the null hypothesis was true. In a meta-analysis, the P-value for the overall effect assesses the overall statistical significance of the difference between the intervention groups, whilst the P-value for the heterogeneity statistic assesses the statistical significance of differences between the effects observed in each study.
  • Paired design
    • A study in which participants or groups of participants are matched (e.g. based on prognostic factors). One member of each pair is then allocated to the experimental (intervention) group and the other to the control group.
  • Pandemic
    • Wikipedia
      A pandemic is an epidemic of infectious disease that is spreading through human populations across a large region; for instance a continent, or even worldwide.
      An epidemic occurring over a very wide area (several countries or continents) and usually affecting a large proportion of the population.
  • Parallel group trial
    • A trial that compares two groups of people concurrently, one of which receives the intervention of interest and one of which is a control group. Some parallel trials have more than two comparison groups and some compare different interventions without including a non-intervention control group. (Also called independent group design.)
  • Parameter
    • Wikipedia
      A quantity defining a theoretical model. Unlike variables, parameters do not relate to actual measurements or attributes of patients.
  • Parametric tests
    • Wikipedia
      Statistical tests that can be applied when the data fall in a normal distribution, that is, when they are spread evenly around the mean, and the frequency distribution curve is bell-shaped or Gaussian.
  • Parental consent
    • Wikipedia
      Parental consent laws (also known as parental involvement or parental notification laws) in some countries require that one or more parents consent to or be notified before their minor child can legally engage in certain activities.
  • Parental notification
    • MeSH
      Reporting to parents or guardians about care to be provided to a minor.
  • Parity
    • MeSH - Wikipedia
      The number of children previously born alive to a woman; for example, 'two-parity women' are women who have had two children and 'zero-parity women' have had no live births.
      Number of births for a given woman, counting a multiple birth pregnancy as one. In some demographic studies, stillbirths do not count toward parity.
      The number of offspring a female has borne. It is contrasted with gravidity, which refers to the number of pregnancies, regardless of outcome.
  • Partial verification bias
    • Occurs when only a selected sample of patients who underwent the index test is verified by the reference standard, and that sample is dependent on the results of the test. For example, patients with suspected coronary artery disease whose exercise test results are positive may be more likely to undergo coronary angiography (the reference standard) than those whose exercise test results are negative.
  • Participant
    • An individual who is studied in a trial, often but not necessarily a patient.
  • Participatory research
    • Research, with the collaboration of those affected by the issue being studied (includes individuals and organizations), for the purpose of taking action or effecting change.
  • Partnership practice
    • MeSH
      A voluntary contract between two or more doctors who may or may not share responsibility for the care of patients, with proportional sharing of profits and losses.
  • Pathogenicity
    • The proportion of persons infected, after exposure to a causative agent, who then develop clinical disease.
  • Patient
    • MeSH - Wikipedia
      A person in contact with the health system seeking attention for a health condition.
      Individuals participating in the health care system for the purpose of receiving therapeutic, diagnostic, or preventive procedures.
  • Patient acceptance of health care
    • MeSH
      The seeking and acceptance by patients of health service.
      Also called healthcare patient acceptance.
  • Patient advocate
    • Wikipedia
      A person who helps a patient work with others who have an effect on the patient's health, including doctors, insurance companies, employers, case managers, and lawyers. A patient advocate helps resolve issues about health care, medical bills, and job discrimination related to a patient's medical condition.
  • Patient advocacy
    • MeSH
      Promotion and protection of the rights of patients, frequently through a legal process.
  • Patient care
    • MeSH
      The services rendered by members of the health profession and non-professionals under their supervision for the benefit of the patient.
  • Patient care management
    • MeSH
      Generating, planning, organizing, and administering medical and nursing care and services for patients.
  • Patient-centered care
    • MeSH
      Design of patient care wherein institutional resources and personnel are organized around patients rather than around specialized departments.
  • Patient education handout
    • Patient education handout [MeSH - publication type]: works consisting of a handout or self-contained informative material used to explain a procedure or a condition or the contents of a specific article in a biomedical journal and written in non-technical language for the patient or consumer.
  • Patient expected event rate
    • The probability of the occurrence of the endpoint or outcome of interest in the patient group of which the individual under consideration is representative.
  • Patient freedom of choice laws
    • MeSH
      Laws requiring patients under managed care programs to receive services from the physician or other provider of their choice. Any willing provider laws take many different forms, but they typically prohibit managed-care organizations from having a closed panel of physicians, hospitals, or other providers.
  • Patient-important outcomes
    • Outcomes that patients value directly. This is in contrast to surrogate, substitute, or physiologic outcomes that clinicians may consider important. One way of thinking about a patient-important outcome is that, were it to be the only thing that changed, patients would be willing to undergo a treatment with associated risk, cost, or inconvenience. This would be true of treatments that ameliorated symptoms or prevented morbidity or mortality. It would not be true of treatments that lowered blood pressure, improved cardiac output, improved bone density, or the like, without improving the quality or increasing the length of life.
  • Patient-mediated interventions
    • A strategy for changing clinician behavior. Any intervention aimed at changing the performance of health care professionals through interactions with, or information provided by or to, patients.
  • Patient participation
    • MeSH - Wikipedia
      Patient participation, also called shared decision making, is patient involvement in the decision-making process in matters pertaining to health.
      Patient involvement in the decision-making process in matters pertaining to health.
  • Patient preference
    • MeSH
      The relative value that patients place on various health states. Preferences are determined by values, beliefs, and attitudes that patients bring to bear in considering what they will gain or lose as a result of a management decision. Explicit enumeration and balancing of benefits and risks that is central to evidence-based clinical practice brings the underlying value judgments involved in making management decisions into bold relief.
      Individual's expression of desirability or value of one course of action, outcome, or selection in contrast to others.
  • Patient-reported outcome
    • Wikipedia
      A patient-reported outcome or PRO is a questionnaire used in a clinical trial or a clinical setting, where the responses are collected directly from the patient.
  • Patient rights
    • MeSH
      Fundamental claims of patients, as expressed in statutes, declarations, or generally accepted moral principles. The term is used for discussions of patient rights as a group of many rights, as in a hospital's posting of a list of patient rights.
  • Patient safety
    • Wikipedia
      Healthcare discipline that emphasizes the reporting, analysis, and prevention of medical error that often lead to adverse healthcare events.
  • Patient satisfaction
    • MeSH
      The degree to which the individual regards the health care service or product or the manner in which it is delivered by the provider as useful, effective, or beneficial.
  • Patient selection
    • MeSH
      Criteria and standards used for the determination of the appropriateness of the inclusion of patients with specific conditions in proposed treatment plans and the criteria used for the inclusion of subjects in various clinical trials and other research protocols.
  • Peer review
    • MeSH - Wikipedia
      Review of a clinical trial by experts chosen by the study sponsor. These experts review the trials for scientific merit, participant safety, and ethical considerations.
      A refereeing process for checking the quality and importance of reports of research. An article submitted for publication in a peer-reviewed journal is reviewed by other experts in the area.
      An organized procedure carried out by a select committee of professionals in evaluating the performance of other professionals in meeting the standards of their specialty. Review by peers is used by editors in the evaluation of articles and other papers submitted for publication. Peer review is used also in the evaluation of grant applications. It is applied also in evaluating the quality of health care provided to patients.
  • Peer-reviewed journal
    • Wikipedia
      A journal in which the articles are vetted by independent referees for quality and interest, and is therefore more highly regarded.
  • Per capita government expenditure on health (PPP int. $)
    • Per capita general government expenditure on health (GGHE) expressed in PPP international dollar.
  • Per capita government expenditure on health at average exchange rate (US$)
    • Per capita general government expenditure on health (GGHE) expressed at average exchange rate for that year in US dollar. Current prices.
  • Per capita total expenditure on health (PPP int. $)
    • Per capita total expenditure on health (THE) expressed in PPP international dollar.
  • Per capita total expenditure on health at average exchange rate (US$)
    • Per capita total expenditure on health (THE) expressed at average exchange rate for that year in US$. Current prices.
  • Per protocol analysis
    • Wikipedia
      An analysis of the subset of participants from a randomized controlled trial who complied with the protocol sufficiently to ensure that their data would be likely to exhibit the effect of treatment. This subset may be defined after considering exposure to treatment, availability of measurements and absence of major protocol violations. The per protocol analysis strategy may be subject to bias as the reasons for non-compliance may be related to treatment.
  • Per protocol set
    • The set of data generated by the subset of subjects who complied with the protocol sufficiently to ensure that these data would be likely to exhibit the effects of treatment, according to the underlying scientific model. Compliance covers such considerations as exposure to treatment, availability of measurements and absence of major protocol violations.
  • Percentile
    • Wikipedia
      A percentile (or centile) is the value of a variable below which a certain percent of observations fall.
      The set of numbers from 0 to 100 that divide a distribution into 100 parts of equal area, or divide a set of ranked data into 100 class intervals with each interval containing 1/100 of the observations. A particular percentile, say the 5th percentile, is a cut point with 5 percent of the observations below it and the remaining 95% of the observations above it.
  • Performance bias
    • Systematic differences between intervention groups in care provided apart from the intervention being evaluated. For example, if participants know they are in the control group, they may be more likely to use other forms of care. If care providers are aware of the group a particular participant is in, they might act differently.  Blinding of study participants (both the recipients and providers of care) is used to protect against performance bias.
  • Performance criteria
    • Concerns how interventions are performed without regard to whether they should be performed. An example would be the acceptable range of results reported for reference cholesterol samples sent to clinical laboratories.
  • Perinatal care
    • MeSH
      The care of a fetus or newborn given before, during, and after delivery from the 28th week of gestation through the 7th day after delivery.
  • Perinatal mortality
    • MeSH - Wikipedia
      Fetal or neonatal death occurring during late pregnancy (at 20 completed weeks of gestational age and later), during childbirth and up to 7 completed days after birth.
      Fetal deaths beginning at 22 completed weeks (154 days) plus deaths of live births within the first seven days after birth. Live births eligible to be considered as perinatal deaths must be at least 500 g, or 22 completed weeks of gestation, or 25 cm in body length to be included in many national perinatal statistics. For international perinatal mortality statistics, live births must have been either 1,000 g or 28 completed weeks gestation or 35 cm in body length.
      Deaths occurring from the 28th week of gestation to the 7th day after birth.
  • Perinatal mortality rate
    • Wikipedia
      The number of fetal deaths after 28 weeks of pregnancy (late fetal deaths) plus the number of deaths to infants under 7 days of age per 1,000 live births.
  • Perinatal period
    • The ICD-10 defines “perinatal” as the time period starting at 22 completed weeks (154 days) gestation and lasting through seven days after birth
  • Perinatology
    • MeSH
      The branch of medicine dealing with the fetus and infant during the perinatal period. The perinatal period begins with the twenty-eighth week of gestation and ends twenty-eight days after birth.
  • Period analysis
    • Observation of a population at a specific period of time. Such an analysis in effect takes a 'snapshot' of a population in a relatively short time period — for example, one year. Most rates are derived from period data and therefore are period rates.
  • Period effect
    • In a cross-over trial: a difference in the measured outcomes from one treatment period to another. This could be caused, for instance, by all patients in a trial naturally healing over time.
  • Period prevalence
    • Wikipedia
      In epidemiology, period prevalence is the proportion of the population with a given disease or condition over a specific period of time.
  • Permuted block design
    • An approach to generating an allocation sequence in which the number of assignments to intervention groups satisfies a specified allocation ratio (such as 1:1 or 2:1) after every "block" of specified size. For example, a block of size 12 would contain 6 A and 6 B with a ratio of 1:1 or 8 A and 4 B with a ratio of 2:1. Generating the allocation sequence involves randomly selecting from all the permutations of assignments that meet the specified ratio.
  • Person-time
    • Cumulative time spent by each individual at risk in the population. Used in the formal expression of mortality rates, and necessary when comparing mortality rates in periods that are different in length for each individual in the population (e.g. before versus after arrival to a camp).
  • Person-time rate
    • A measure of the incidence rate of an event, e.g., a disease or death, in a population at risk over an observed period to time, that directly incorporates time into the denominator.
  • Person-years
    • The average number of years that each participant is followed up for, multiplied by the number of participants.
  • Personal narratives
    • Personal narratives [MeSH - publication type]; works consisting of accounts of personal experience in relation to a particular field or of participation in related activities or autobiographical accounts.
  • Personhood
    • MeSH
      The state or condition of being a human individual accorded moral and/or legal rights. Criteria to be used to determine this status are subject to debate, and range from the requirement of simply being a human organism to such requirements as that the individual be self-aware and capable of rational thought and moral agency.
  • Peto method
    • Wikipedia
      A way of combining odds ratios that has become widely used in meta-analysis.  It is especially used to analyze trials with time to event outcomes. The calculations are straightforward and understandable, but this method produces biased results in some circumstances. It is a fixed-effect model.
      A statistical method to combine individual studies, derived from the Mantel-Haenszel's procedure, in which the observed outcomes in the index group are compared with the expected ones, and weighting by its variance.18 It should only be used when the sample size of the arms of a study are balanced and the effect size is close to the null value.
  • Pharmacoepidemiology
    • MeSH - Wikipedia
      The study of the use and effects of drugs in large groups of people.
      The science concerned with the benefit and risk of drugs used in populations and the analysis of the outcomes of drug therapies. Pharmacoepidemiologic data come from both clinical trials and epidemiological studies with emphasis on methods for the detection and evaluation of drug-related adverse effects, assessment of risk vs benefit ratios in drug therapy, patterns of drug utilization, the cost-effectiveness of specific drugs, methodology of postmarketing surveillance, and the relation between pharmacoepidemiology and the formulation and interpretation of regulatory guidelines.
  • Pharmacokinetics
    • MeSH - Wikipedia
      The processes (in a living organism) of absorption, distribution, metabolism, and excretion of a drug or vaccine.
      Dynamic and kinetic mechanisms of exogenous chemical and drug absorption; biological transport; tissue distribution; biotransformation; elimination; and toxicology as a function of dosage, and rate of metabolism. it includes toxicokinetics, the pharmacokinetic mechanism of the toxic effects of a substance. ADME and ADMET are short-hand abbreviations for absorption, distribution, metabolism, elimination and toxicology.
  • Pharmacopoeia
    • MeSH - Wikipedia
      A book containing directions for the identification of samples and the preparation of compound medicines, and published by the authority of a government or a medical or pharmaceutical society.
      Authoritative treatises on drugs and preparations, their description, formulation, analytic composition, physical constants, main chemical properties used in identification, standards for strength, purity, and dosage, chemical tests for determining identity and purity, etc. They are usually published under governmental jurisdiction (e.g., USP, the United States Pharmacopoeia; BP, British Pharmacopoeia; P. Helv., the Swiss Pharmacopoeia). They differ from formularies in that they are far more complete: formularies tend to be mere listings of formulas and prescriptions.
      Pharmacopoeias [MeSH - publication type]: authoritative works containing lists of drugs and preparations, their description, formulation, analytic composition, main chemical properties, standards for strength, purity, and dosage, chemical tests for determining identity, etc. They have the status of a standard.
  • Phase I clinical trials
    • MeSH - Wikipedia
      First trials of a new active ingredient or new formulation in humans, often carried out in healthy volunteers.
      Studies performed to evaluate the safety of diagnostic, therapeutic, or prophylactic drugs, devices, or techniques in healthy subjects and to determine the safe dosage range (if appropriate). These tests also are used to determine pharmacologic and pharmacokinetic properties (toxicity, metabolism, absorption, elimination, and preferred route of administration). They involve a small number of persons and usually last about 1 year. This concept includes phase I studies conducted both in the U.S. and in other countries.
      Clinical trial, phase I [MeSH - publication type]: work that is the report of a pre-planned, usually controlled, clinical study of the safety and efficacy of diagnostic, therapeutic, or prophylactic drugs, devices, or techniques based on a small number of healthy persons and conducted over the period of about a year in either the United States or a foreign country.
  • Phase II clinical trials
    • MeSH - Wikipedia
      Trials performed in a limited number of subjects and often of a comparative (e.g. placebo-controlled) design, to demonstrate therapeutic activity and to assess the short-term safety of the active ingredient in patients suffering from a disease or condition for which the active ingredient is intended.
      Studies that are usually controlled to assess the effectiveness and dosage (if appropriate) of diagnostic, therapeutic, or prophylactic drugs, devices, or techniques. These studies are performed on several hundred volunteers, including a limited number of patients with the target disease or disorder, and last about two years. This concept includes phase II studies conducted in both the U.S. and in other countries.
      Clinical trial, phase II [MeSH - publication type]: work that is a report of a pre-planned, usually controlled, clinical study of the safety and efficacy of diagnostic, therapeutic, or prophylactic drugs, devices, or techniques based on several hundred volunteers, including a limited number of patients, and conducted over a period of about two years in either the United States or a foreign country.
  • Phase III clinical trials
    • MeSH - Wikipedia
      Trials including larger (and possibly varied) patient groups, with the purpose of determining the short-and long-term safety/efficacy balance of formulation(s) of the active ingredient, and of assessing its overall and relative therapeutic value.
      Comparative studies to verify the effectiveness of diagnostic, therapeutic, or prophylactic drugs, devices, or techniques determined in phase II studies. During these trials, patients are monitored closely by physicians to identify any adverse reactions from long-term use. These studies are performed on groups of patients large enough to identify clinically significant responses and usually last about three years. This concept includes phase III studies conducted in both the U.S. and in other countries.
      Clinical trial, phase III [MeSH - publication type]: work that is a report of a pre-planned, usually controlled, clinical study of the safety and efficacy of diagnostic, therapeutic, or prophylactic drugs, devices, or techniques after phase II trials. A large enough group of patients is studied and closely monitored by physicians for adverse response to long-term exposure, over a period of about three years in either the United States or a foreign country.
  • Phase IV clinical trials
    • MeSH - Wikipedia
      Studies performed after marketing of the pharmaceutical product to discover rare and remote side-effects.
      Planned post-marketing studies of diagnostic, therapeutic, or prophylactic drugs, devices, or techniques that have been approved for general sale. These studies are often conducted to obtain additional data about the safety and efficacy of a product. This concept includes phase IV studies conducted in both the U.S. and in other countries.
      Clinical trial, phase IV [MeSH - publication type]: work that is a report of a planned post-marketing study of diagnostic, therapeutic, or prophylactic drugs, devices, or techniques that have been approved for general sale after clinical trials, phases I, II, and III. These studies, conducted in the United States or a foreign country, often garner additional data about the safety and efficacy of a product.
  • Physician
    •  MeSH - Wikipedia
      A person who has completed studies in medicine at the university level. To be legally licensed for the independent practice of medicine, (s)he must, in most cases, undergo additional postgraduate training in a hospital.
      Individuals licensed to practice medicine.
  • Physicians ratio
    • The number of physicians available per every 10,000 inhabitants in a population, at a given year, for a given country, territory, or geographic area.
  • Pie chart
    • Wikipedia
      A graphical method of representing the frequency distribution of a set of categorical data in the shape of a pie.
      A circular chart in which the size of each "slice'' is proportional to the frequency of each category of a variable.
  • Pilot study
    • MeSH - Wikipedia
      The initial study examining a new method or treatment.
      A preliminary study to test the feasibility of the protocol, before implementing the study proper. It may also be called “pre-test”.
      A smaller version or trial run of a larger study that is conducted in preparation for that study; can involve pre-testing or ‘trying out’ a research tool such as a data-collecting form.
      Small-scale tests of methods and procedures to be used on a larger scale if the pilot study demonstrates that these methods and procedures can work.
  • Placebo
    • MeSH - Wikipedia
      A placebo is an inactive pill, liquid, or powder that has no treatment value. In clinical trials, experimental treatments are often compared with placebos to assess the treatment's effectiveness.
      An inactive substance or treatment that looks the same as, and is given the same way as, an active drug or treatment being tested. The effects of the active drug or treatment are compared to the effects of the placebo.
      An inactive substance or procedure administered to a participant, usually to compare its effects with those of a real drug or other intervention, but sometimes for the psychological benefit to the participant through a belief that s/he is receiving treatment. Placebos are used in clinical trials to blind people to their treatment allocation. Placebos should be indistinguishable from the active intervention to ensure adequate blinding.
      Any dummy medication or treatment. Although placebos originally were medicinal preparations having no specific pharmacological activity against a targeted condition, the concept has been extended to include treatments or procedures, especially those administered to control groups in clinical trials in order to provide baseline measurements for the experimental protocol.
  • Placebo controlled study
    • Wikipedia
      A method of investigation of drugs in which an inactive substance (the placebo) is given to one group of participants, while the drug being tested is given to another group. The results obtained in the two groups are then compared to see if the investigational treatment is more effective in treating the condition.
      Refers to a clinical study in which the control patients receive a placebo.
  • Placebo effect
    • MeSH - Wikipedia
      A physical or emotional change, occurring after a substance is taken or administered, that is not the result of any special property of the substance. The change may be beneficial, reflecting the expectations of the participant and, often, the expectations of the person giving the substance.
      The phenomenon where, in an intervention study, subjects receiving, without knowing, an inert drug, show an improvement or perception of improvement in their condition, probably due to their expectations.
      An effect usually, but not necessarily, beneficial that is attributable to an expectation that the regimen will have an effect, i.e., the effect is due to the power of suggestion.
  • Placebo therapy
    • An inactive treatment or procedure that is intended to mimic as closely as possible a therapy in a clinical trial. Also called sham therapy.
  • Plagiarism
    • MeSH - Wikipedia
      The wrongful appropriation, close imitation, or purloining and publication, of another author's language, thoughts, ideas, or expressions, and the representation of them as one's own original work.
      Passing off as one's own the work of another without credit.
  • Planned analyses
    • Statistical analyses specified in the trial protocol; that is, planned in advance of data collection. In contrast to unplanned analyses. (Also called a priori analyses, pre-specified analyses.)
  • Point estimate
    • Wikipedia
      The results (e.g. mean, weighted mean difference, odds ratio, risk ratio or risk difference) obtained in a sample (a study or a meta-analysis) which are used as the best estimate of what is true for the relevant population from which the sample is taken.
      Most likely value for the parameter of interest (e.g. crude mortality rate) obtained through a sample survey. A point estimate should always be accompanied by a confidence interval.
  • Point prevalence
    • Wikipedia
      In epidemiology, point prevalence is a measure of the proportion of people in a population who have a disease or condition at a particular time, such as a particular date.
      The amount of a particular disease present in a population at a single point in time.
  • Poisson distribution
    • MeSH - Wikipedia
      A statistical distribution with known properties used as the basis of analyzing the number of occurrences of relatively rare events occurring over time.
      A distribution function used to describe the occurrence of rare events or to describe the sampling distribution of isolated counts in a continuum of time or space.
  • Policy
    • Wikipedia
      A set of statements or commitments to pursue courses of action aimed at achieving defined goals of public or private institutions.
      A policy is a course or principle of action adopted or proposed by an organization or individual.
      A policy represents the way in which government or an organization seeks to achieve the objectives it has set.
  • Policy-maker
    • A person with power to influence or determine policies and practices at an international, national, regional or local level. Policy-makers have the responsibility and commitment for making the appropriate use of the best available evidence for policy-making and decision-taking. The policy-maker is someone who sets the plan pursued by a government or organization, a person whose actions and opinions strongly influence the course of events.
  • Policy making
    • MeSH
      The decision process by which individuals, groups or institutions establish policies pertaining to plans, programs or procedures.
  • Policy question
    • This is a relevant question (gap) concerning policies and/or strategic issues or directions in a specific context (governments, organizations, etc.) that has to be addressed by a policy-maker (decision-maker) and affects the ‘real’ world by guiding the decisions that are made. These policy questions may be formally written or not. Most organizations identify their gaps (policy questions) and define policies to solve them.
  • Polyclinic
    • Wikipedia
      A type of health provider that provides ambulatory health care for more than one specialty of services.
  • Pooled estimate
    • Estimate based on combining data from 2 or more samples.
  • Pooling
    • The estimation of a summary (or pooled) effect size after the statistical aggregation of the individual studies.
  • Population
    • MeSH
      An entire set of persons, animals, objects or events which the researcher intends to study.
      All the inhabitants of a country, territory, or geographic area, total or for a given sex and/or age group, at a specific point of time. In demographic terms it is the total number of inhabitants of a given sex and/or age group that actually live within the border limits of the country, territory, or geographic area at a specific point of time, usually mid-year. The mid-year population refers to the actual population at July 1st.
      The total number of individuals inhabiting a particular region or area.
  • Population-based survey
    • A survey where the sample is representative of the population being studied.
  • Population characteristics
    • MeSH
      Qualities and characterization of various types of populations within a social or geographic group, with emphasis on demography, health status, and socioeconomic factors.
  • Population control
    • MeSH - Wikipedia
      A broad concept that addresses the relationship between fertility, mortality, and migration, but is most commonly used to refer to efforts to slow population growth through action to lower fertility. It should not be confused with family planning.
      Human population control is the practice of artificially altering the rate of growth of a human population.
      Includes mechanisms or programs which control the numbers of individuals in a population of humans or animals.
  • Population density
    • MeSH - Wikipedia
      Population per unit of land area; for example, people per square mile or people per square kilometer of arable land.
      Number of individuals in a population relative to space.
  • Population distribution
    • The patterns of settlement and dispersal of a population.
  • Population dynamics
    • MeSH - Wikipedia
      The branch of life sciences that studies short- and long-term changes in the size and age composition of populations, and the biological and environmental processes influencing those changes.
      The pattern of any process, or the interrelationship of phenomena, which affects growth or change within a population.
  • Population genetics
    • MeSH - Wikipedia
      The study of allele frequency distribution and change under the influence of the four main evolutionary processes: natural selection, genetic drift, mutation and gene flow.
      The discipline studying genetic composition of populations and effects of factors such as genetic selection, population size, mutation, migration, and genetic drift on the frequencies of various genotypes and phenotypes using a variety of genetic techniques.
  • Population groups
    • MeSH
      Individuals classified according to their sex, racial origin, religion, common place of living, financial or social status, or some other cultural or behavioral attribute.
  • Population growth
    • MeSH - Wikipedia
      Population growth is the change in a population over time, and can be quantified as the change in the number of individuals of any species in a population using "per unit time" for measurement. In biology, the term population growth is likely to refer to any known organism, but this article deals mostly with the application of the term to human populations in demography.
      Increase, over a specific period of time, in the number of individuals living in a country or region.
  • Population health
    • Wikipedia
      The health outcomes of a group of individuals, including the distribution of such outcomes within the group.
      Population health is not merely the sum of the health of individuals; it also entails consideration of the nature of the distribution of health throughout the population.
  • Population (in thousands) total
    • De facto population in a country, area or region as of 1 July of the year indicated. Figures are presented in thousands.
  • Population living in urban areas
    • The percentage of de facto population living in areas classified as urban according to the criteria used by each area or country as of 1 July of the year indicated.
  • Population median age (years)
    • Age that divides the population in two parts of equal size, that is, there are as many persons with ages above the median as there are with ages below the median.
  • Population projection
    • Wikipedia
      Computation of future changes in population numbers, given certain assumptions about future trends in the rates of fertility, mortality, and migration. Demographers often issue low, medium, and high projections of the same population, based on different assumptions of how these rates will change in the future.
  • Population proportion over 60
    • The percentage of de facto population aged 60 years and older in a country, area or region as of 1 July of the year indicated.
      The percentage of total population of a country, territory, or geographic area, 60 years of age and over, total or for a given sex and at a specific point of time, usually mid-year.
      Also called proportion of population 60 years and older.
  • Population proportion under 15
    • The percentage of de facto population aged 0-14 years in a country, area or region as of 1 July of the year indicated.
      The percentage of total population of a country, territory, or geographic area, under 15 years of age, total or a given sex and at a specific point of time, usually mid-year.
      Also called proportion of population less than 15 years old.
  • Population-proportional sampling
    • Approach to selection of clusters or households to be sampled, whereby more populous sections of the study area are allocated proportionately more clusters or households.
  • Population pyramid
    • Wikipedia
      A population pyramid, also called age-sex pyramid and age structure diagram, is a graphical illustration that shows the distribution of various age groups in a human population (typically that of a country or region of the world), which normally forms the shape of a pyramid.
      Graph of the sex and age-group distribution of the population. Used in mortality studies to observe possible alterations in the demographics of the population as a result of high mortality or population loss in a particular age group or sex.
  • Population stratification
    • Wikipedia
      Describes the situation in which a population may be composed of multiple sub-groups of different ethnicity; case and control group differences in the mix can confound the comparison and lead to spurious genetic associations.
  • Population study
    • Wikipedia
      A study of a group of individuals taken from the general population who share a common characteristic, such as age, sex, or health condition. This group may be studied for different reasons, such as their response to a drug or risk of getting a disease.
  • Population surveillance
    • MeSH
      Ongoing scrutiny of a population (general population, study population, target population, etc.), generally using methods distinguished by their practicability, uniformity, and frequently their rapidity, rather than by complete accuracy.
  • Position-specific scoring matrix
    • MeSH - Wikipedia
      A position weight matrix (PWM), also called position-specific weight matrix (PSWM) or position-specific scoring matrix (PSSM), is a commonly used representation of motifs (patterns) in biological sequences.
      Tabular numerical representations of sequence motifs displaying their variability as likelihood values for each possible residue at each position in a sequence. Position-specific scoring matrices (PSSMs) are calculated from position frequency matrices.
  • Positive correlation
    • A positive correlation between two variables implies that as one variable gets bigger the value of the other variable also becomes bigger.
  • Positive likelihood ratio
    • Wikipedia
      The ratio of the probability that an individual with the target condition has a positive test result to the probability that an individual without the target condition has a positive test result. This is the same as the ratio (sensitivity/1-specificity).
  • Positive predictive value
    • Wikipedia
      The positive predictive value, or precision rate, or post-test probability of disease, is the proportion of patients with positive test results who are correctly diagnosed. It is the most important measure of a diagnostic method as it reflects the probability that a positive test reflects the underlying condition being tested for. Its value does however depend on the prevalence of the disease, which may vary.
      In screening/diagnostic tests: a measure of the usefulness of a screening/diagnostic test. It is the proportion of those with a positive test result who have the disease, and can be interpreted as the probability that a positive test result is correct. It is calculated as follows: PPV = Number with a positive test who have disease/Number with a positive test.
  • Positive predictive value of case definition
    • Ability of the case definition to identify real cases or the proportion of true cases of the disease that meet the case definition.
  • Positive predictive value of detecting outbreaks/cases
    • Ability of the surveillance system to detect real alerts, i.e. confirmed alerts (after verification)/all alerts detected.
  • Positive study
    • A study with results indicating a beneficial effect of the intervention being studied.  The term can generate confusion because it can refer to both statistical significance and the direction of effect; studies often have multiple outcomes; the criteria for classifying studies as negative or positive are not always clear; and, in the case of studies of risk or undesirable effects, ‘positive’ studies are ones that show a harmful effect.
  • Posterior distribution
    • Wikipedia
      The outcome of Bayesian statistical analysis. A probability distribution describing how likely different values of an outcome (e.g. treatment effect) are. It takes into account the belief before the study (the prior distribution) and the observed data from the study.
  • Posterior probability
    • Wikipedia
      The probability of an event after a diagnostic result, that is, the updated prior probability. It can be calculated from the prior probability using Bayes's rule.
  • Post-exposure prophylaxis
    • MeSH
      The prevention of infection or disease following exposure to a pathogen. This is most frequently addressed by administering a vaccine or anti-viral medication following exposure to a virus.
  • Postmarketing product surveillance
    • MeSH
      Surveillance of drugs, devices, appliances, etc., for efficacy or adverse effects, after they have been released for general sale.
  • Postnatal care
    • MeSH
      The care provided a woman following the birth of a child.
  • Post-neonatal mortality rate
    • The annual number of deaths of infants ages 28 days to 1 year per 1,000 live births in a given year.
      A ratio expressing the number of deaths among children from 28 days up to but not including 1 year of age during a given time period divided by the number of lives births reported during the same time period. The postneonatal mortality rate is usually expressed per 1,000 live births.
  • Postpartum
    • MeSH
      In females, the period that is shortly after giving birth (parturition).
      Also called postpartum period, puerperium.
  • Post-term birth
    • A live birth or stillbirth that takes place after 42 completed weeks of gestational age.
  • Post-test odds
    • The odds that the patient has the target disorder after the test is carried out (pre-test odds x likelihood ratio).
  • Post-test probability
    • The proportion of patients with that particular test result who have the target disorder (post test odds/[1 + post-test odds]).
  • Power
    • Wikipedia
      In statistics: the probability of rejecting the null hypothesis when a specific alternative hypothesis is true. The power of a hypothesis test is one minus the probability of Type II error.  In clinical trials, power is the probability that a trial will detect, as statistically significant, an intervention effect of a specified size. If a clinical trial had a power of 0.80 (or 80%), and assuming that the pre-specified treatment effect truly existed, then if the trial was repeated 100 times, it would find a statistically significant treatment effect in 80 of them.  Ideally we want a test to have high power, close to maximum of one (or 100%). For a given size of effect, studies with more participants have greater power. Studies with a given number of participants have more power to detect large effects than small effect.  (Also called statistical power.)
  • Practice-based research
    • Research that is grounded in, informed by, and intended to improve practice with the goal of improving the health of patients.
  • Practice guideline
    • MeSH
      Directions or principles presenting current or future rules of policy for assisting health care practitioners in patient care decisions regarding diagnosis, therapy, or related clinical circumstances. The guidelines may be developed by government agencies at any level, institutions, professional societies, governing boards, or by the convening of expert panels. The guidelines form a basis for the evaluation of all aspects of health care and delivery.
      Practice guideline [MeSH - publication type]: work consisting of a set of directions or principles to assist the health care practitioner with patient care decisions about appropriate diagnostic, therapeutic, or other clinical procedures for specific clinical circumstances. Practice guidelines may be developed by government agencies at any level, institutions, organizations such as professional societies or governing boards, or by the convening of expert panels. They can provide a foundation for assessing and evaluating the quality and effectiveness of health care in terms of measuring improved health, reduction of variation in services or procedures performed, and reduction of variation in outcomes of health care delivered.
  • Pragmatic trial
    • A trial that aims to test a treatment policy in a 'real life' situation, when many people may not receive all of the treatment, and may use other treatments as well.  This is as opposed to an explanatory trial, which is done under ideal conditions and is trying to determine whether a therapy has the ability to make a difference at all (i.e. testing its efficacy).
  • Precautionary principle
    • Wikipedia
      The precautionary principle states that if an action or policy has a suspected risk of causing harm to the public or to the environment, in the absence of scientific consensus that the action or policy is harmful, the burden of proof that it is not harmful falls on those taking the action.
      Expresses the conditions for decisions to implement prevention: scientific uncertainty, an acceptable balance of benefits and harms, and responsibility.
  • Precision
    • Wikipedia
      In statistics: a measure of the likelihood of random errors in the results of a study, meta-analysis or measurement. The greater the precision, the less random error. Confidence intervals around the estimate of effect from each study are one way of expressing precision, with a narrower confidence interval meaning more precision.
      In trial searching: the proportion of relevant articles identified by a search strategy expressed as a percentage of all articles (relevant and irrelevant) identified by that strategy. Highly sensitive strategies tend to have low levels of precision. It is calculated as follows: Precision = Number of relevant articles/Number of articles identified. Also called positive predictive value.
  • Preclinical drug evaluation
    • MeSH
      Refers to the testing of experimental drugs in the test tube or in animals - the testing that occurs before trials in humans may be carried out.
      Preclinical testing of drugs in experimental animals or in vitro for their biological and toxic effects and potential clinical applications.
  • Preclinical research
    • Wikipedia
      Preclinical research is research in basic science, which precedes the clinical trials, and is almost purely based on theory and animal experiments.
      Research using animals to find out if a drug, procedure, or treatment is likely to be useful. Preclinical studies take place before any testing in humans is done.
  • Predictive factor
    • A situation or condition that may increase a person's risk of developing a certain disease or disorder.
  • Predictive value
    • MeSH - Wikipedia
      The frequency with which a positive diagnostic test actually signifies disease.
      In screening and diagnostic tests, the probability that a person with a positive test is a true positive (i.e., has the disease), is referred to as the predictive value of a positive test; whereas, the predictive value of a negative test is the probability that the person with a negative test does not have the disease. Predictive value is related to the sensitivity and specificity of the test.
      Also called predictive value of tests.
  • Pregnancy
    • MeSH
      The status during which female mammals carry their developing young (embryos or fetuses) in utero before birth, beginning from fertilization to birth.
  • Pregnancy complications
    • MeSH
      Conditions or pathological processes associated with pregnancy. They can occur during or after pregnancy, and range from minor discomforts to serious diseases that require medical interventions. They include diseases in pregnant females, and pregnancies in females with diseases.
  • Pregnancy in adolescence
    • MeSH - Wikipedia
      A teenaged or underaged girl (usually within the ages of 13–19) becoming pregnant.
      Pregnancy in human adolescent females under the age of 19.
      Also called adolescent pregnancy, teenage pregnancy.
  • Pregnancy outcome
    • MeSH
      Results of conception and ensuing pregnancy, including live birth; stillbirth; spontaneous abortion; induced abortion. The outcome may follow natural or artificial insemination or any of the various assisted reproductive techniques, such as embryo transfer or fertilization in vitro.
  • Pregnancy rate
    • MeSH
      The ratio of the number of conceptions (conception) including live birth; stillbirth; and fetal losses, to the mean number of females of reproductive age in a population during a set time period.
  • Pregnancy-related death
    • The death of a woman while pregnant or within 42 days of termination of pregnancy, irrespective of the cause of death.
  • Pregnancy trimesters
    • MeSH
      The three approximately equal periods of a normal human pregnancy. Each trimester is about three months or 13 to 14 weeks in duration depending on the designation of the first day of gestation.
  • Pregnancy wastage
    • The term used when the couple is able to conceive, but unable to produce a live birth.
  • Prejudice
    • MeSH
      A preconceived judgment made without adequate evidence and not easily alterable by presentation of contrary evidence.
  • Premature labor
    • MeSH
      Onset of obstetric labor before term (term birth) but usually after the fetus has become viable. In humans, it occurs sometime during the 29th through 38th week of pregnancy. Tocolysis inhibits premature labor and can prevent the birth of premature infants (infant, premature).
      Also called premature obstetric labor, preterm labor
  • Premature rupture of membranes
    • MeSH - Wikipedia
      Rupture before onset of labor.
      Spontaneous tearing of the membranes surrounding the fetus any time before the onset of obstetric labor. Preterm PROM is membrane rupture before 37 weeks of gestation.
  • Preparedness
    • Wikipedia
      Activities and measures taken in advance to ensure effective response to the impact of hazards, including the issuance of timely and effective early warnings and the temporary evacuation of people and property from threatened locations.
      Pre-disaster activities, including an overall strategy, policies, and institutional and management structures, that are geared to helping at-risk communities safeguard their lives and assets by being alert to hazards and taking appropriate action in the face of an imminent threat or the actual onset of a disaster.
  • Pre-post design with comparison group – quasi-experimental
    • In this case, to the simple pre-post design a comparison/control group is added that undergoes the same evaluation procedures as before but does not receive the intervention. With this design one can demonstrate that the effects are most likely due to the intervention, but some critics could still say that there were pre-selection or context effects that made the intervention group more likely to show results than the comparison/control group: e.g. having less risk factors.
  • Pre-post design without comparison group – naturalistic
    • The pre- and post-test design (also called naturalistic design) is a simple way to plan an outcome evaluation without the benefits of a control group. In this design, the only people measured are those who receive the intervention. They are tested on their knowledge, attitudes or intentions, for example, before and after the intervention. The differences between the two measurements are then checked for statistical significance. The advantage of this design is its simplicity and the fact that it is not very time consuming. The major drawback is that without a control group, it is difficult to know whether the results are really due to the intervention, or to some other confounding factors.
  • Preschool child
    • MeSH
      A child between the ages of 2 and 5.
  • Preterm birth
    • MeSH - Wikipedia
      A live birth or stillbirth that takes place after at least 20 but before 37 completed weeks of gestational age.
      Delivery before 37 completed weeks of gestation (less than 259 days).
      Childbirth before 37 weeks of pregnancy (259 days from the first day of the mother's last menstrual period, or 245 days after fertilization).
      Also called premature birth, preterm delivery.
  • Preterm premature rupture of membranes
    • Wikipedia
      Rupture before onset of labor and leading to a preterm delivery.
  • Pre-test
    • A preliminary study to test the feasibility and appropriateness of a questionnaire, before implementing the study proper.
  • Pre-test odds
    • The odds of the target condition being present before the results of a diagnostic test are available.
      The odds that the patient has the target disorder before the test is carried out (pre-test probability/[1 – pre-test probability]).
  • Pre-test/post-test design
    • An experimental research design in which measurements of the groups are made both before and after an intervention.
  • Pre-test probability
    • The probability of the target condition being present before the results of a diagnostic test are available.
      The proportion of people with the target disorder in the population at risk at a specific time (point prevalence) or time interval (period prevalence). Prevalence may depend on how a disorder is diagnosed.
  • Prevalence
    • MeSH - Wikipedia
      In epidemiology, the prevalence of a disease in a statistical population is defined as the total number of cases of the disease in the population at a given time, or the total number of cases in the population, divided by the number of individuals in the population. It is used as an estimate of how common a condition is within a population over a certain period of time.
      The overall occurrence of a particular condition in a specific population at a specific point of time.
      The proportion of a population having a particular condition or characteristic: e.g. the percentage of people in a city with a particular disease, or who smoke.
      Prevalence is the proportion of people in a population who have some attribute or condition at a given point in time or during a specified time period.
      The total number of cases of a given disease in a specified population at a designated time. It is differentiated from incidence, which refers to the number of new cases in the population at a given time.
  • Prevalence of exclusive breastfeeding through 120 days of age
    • The number of children who, from birth until the end of the forth month of life, are fed exclusively breast milk, expressed as a percentage of the corresponding mid-year population, for a given year, in a given country, territory, or geographic area.
  • Prevalence of moderate and severe nutritional deficiency in children less than 5 years
    • The number of prevalent cases of moderate and severe nutritional deficiency in children under 5 year of age detected in a given year, expressed as a percentage of the corresponding mid-year population, for a given country, territory, or geographic area. Under-5 moderate and severe nutritional deficiency is defined as any weight-for-age (W/A) ratio less than minus two standard deviations (-2SD) from the reference median.
  • Prevalence of use of contraceptive methods in women
    • The number women aged 15 to 49 years who use any type of contraceptive method, at a specific point in time, expressed as a percentage of the corresponding mid-year population, for a given year, in a given country, territory, or geographic area. Contraceptive methods include female and male sterilization, injectable and oral contraceptives, intrauterine devices, diaphragms, spermicides, condoms, rhythm method and withdrawal.
  • Prevalence rate
    • The number of people having a particular disease at a given point in time per 1,000 population at risk.
      The proportion of persons in a population who have a particular disease or attribute at a specified point in time or over a specified period of time.
  • Prevalence study
    • A type of cross-sectional study that measures the prevalence of a characteristic.
  • Prevention
    • Wikipedia
      In medicine, action taken to decrease the chance of getting a disease or condition.
      An intervention or interventions that interrupts the web of causality leading to one or more aspects of ill health.
  • Prevention trials
    • Refers to trials to find better ways to prevent disease in people who have never had the disease or to prevent a disease from returning. These approaches may include medicines, vaccines, vitamins, minerals, or lifestyle changes.
  • Preventive health services
    • MeSH
      Services designed for health promotion and prevention of disease.
  • Preventive intervention
    • Prevention intervention describes an activity that will be carried out in order to prevent substance use behavior. Prevention interventions can be realized in different settings and with different methods and contents. The duration can vary between one-off activities and long-term projects running for several months or more.
  • Preventive medicine
    • MeSH - Wikipedia
      Preventive medicine or preventive care refers to measures taken to prevent diseases (or injuries) rather than curing them or treating their symptoms.
      A medical specialty primarily concerned with prevention of disease (primary prevention) and the promotion and preservation of health in the individual.
  • Prima facie
    • Wikipedia
      A term used to describe bioethical principles as neither rules of thumb nor absolute prescriptions but rather as binding in all cases unless an obligation found in one principle conflicts with another. In such situations, balancing of competing principles is undertaken using the technique of specification.
  • Primary care
    • MeSH Wikipedia
      Medical care provided by the clinician of first contact for the patient. Typically, the primary care physician is a general practitioner, family practitioner, primary care internist, or primary care pediatrician. Primary care may also be administered by health professionals other than physicians, notably specially trained nurses (nurse practitioners) and paramedics. Usually, a general practitioner, family practitioner, nurse practitioner, or paramedic provides only primary care services, but an individual with specialty qualifications may provide primary care, alone or in combination with referral services. Thus, it is the nature of the contact (first vs. referred) that determines the care designation rather than the qualifications of the practitioner.
      The first level contact with people taking action to improve health in a community.
      Essential health care based on practical, scientifically sound and socially acceptable methods and technology made universally accessible to individuals and families in the community through their full participation and at a cost that the community and the country can afford to maintain at every stage of their development in the spirit of self-determination.
      Primary care is that aspect of a health services system that assures person focused care over time to a defined population, accessibility to facilitate receipt of care when it is first needed, comprehensiveness of care in the sense that only rare or unusual manifestations of ill health are referred elsewhere, and coordination of care such that all facets of care (wherever received) are integrated.
      Care which provides integrated, accessible health care services by clinicians who are accountable for addressing a large majority of personal health care needs, developing a sustained partnership with patients, and practicing in the context of family and community.
      Also called primary health care.
  • Primary care practice-based research
    • Research that is grounded in, informed by, and intended to improve primary care practice with the goal of improving the health of patients.
  • Primary care research
    • Research directed at understanding and improving the primary care function as defined by the Institute of Medicine ("the provision of integrated, accessible healthcare services by clinicians that are accountable for addressing a large majority of personal healthcare needs, developing a sustained partnership with patients, and practicing within the context of family and community"). Primary care research includes theoretical and methodological research, health care research (investigations of the components of the primary care function itself), clinical research, and health systems research (including educational research, translational research, and health policy research).
  • Primary care setting
    • Medical care facility that offers first contact health care only. Patients requiring specialized medical care are referred elsewhere. Some primary care centers provide a mixture of primary and referred care. Thus, it is the nature of the service provided (first contact) rather than the setting per se that distinguishes primary from more advanced levels of care.
  • Primary endpoint
    • The main result that is measured at the end of a study to see if a given treatment worked (e.g., the number of deaths or the difference in survival between the treatment group and the control group). What the primary endpoint will be is decided before the study begins.
  • Primary infertility
    • Primary infertility means that the couple has never conceived, despite regular unprotected intercourse for a period of 12 months (medical definition).
      Percentage of women who have been married for the past five years, who have ever had sexual intercourse, who have not used contraception during the past five years, and who have not had any births (demographic definition).
  • Primary nursing care
    • MeSH
      The primary responsibility of one nurse for the planning, evaluation, and care of a patient throughout the course of illness, convalescence, and recovery.
  • Primary outcome
    • The outcome of greatest importance.
  • Primary prevention
    • MeSH - Wikipedia
      Interruption of the chain of causality at a point or points before a physiological or psychological abnormality is identifiable.
      Specific practices for the prevention of disease or mental disorders in susceptible individuals or populations. These include health promotion, including mental health; protective procedures, such as communicable disease control; and monitoring and regulation of environmental pollutants. Primary prevention is to be distinguished from secondary prevention and tertiary prevention.
  • Primary research
    • Wikipedia
      Individual studies such as randomized controlled trials, cohort studies, case-control studies, cross-sectional studies, etc.
      Any investigation study (or trial) that is designed to investigate a hypothesized cause-effect relation by modifying the supposed causal factor(s) in the study population. A trial is an umbrella term for a variety of designs, including uncontrolled trials, controlled trials and randomized controlled trials.
      ‘Original research’ in which data are first collected. The term ‘primary research’ is sometimes used to distinguish it from secondary research (reanalysis of previously collected data), meta-analysis and other ways of combining studies (such as economic analysis and decision analysis). However, because systematic reviews can provide answers not possible from individual studies they can also be considered to be primary research.
      Also called primary level research.
  • Primary sources
    • Wikipedia
      Primary sources are reports of original studies or the raw data.
  • Primary study
    • ‘Original research’ in which data are collected. The term primary study is sometimes used to distinguish it from a secondary study (re-analysis of previously collected data), meta-analysis, and other ways of combining studies (such as economic analysis and decision analysis). (Also called original study.)
  • Primigravida
    • Wikipedia
      A woman pregnant for the first time.
  • Primordial prevention
    • Intervention at the most distal point in the chain of causality. It is certain that there is a web of interactions that determine the state of health, from those that are most distal to those that are most proximal. The most distal are likely to be the political context in which the determinants are operative, followed by aspects of policy (health, social, environmental), followed by the context of social as well as medical contacts in communities, followed by individual social and behavioral characteristics (such as social isolation and health behaviors), followed by physiological states such as are related to perceived stressors. When interventions are designed to prevent the occurrence of a risk state, they are known as primary prevention. In a web of determinants, several interventions might be considered “primary”. Primordial prevention occurs when there is a focus on a more antecedent primary preventive strategy. The most effective prevention focuses on the weakest part of the web and not necessarily on the most proximal.
  • Principal component analysis
    • MeSH
      Mathematical procedure that transforms a number of possibly correlated variables into a smaller number of uncorrelated variables called principal components.
  • Principles
    • Four prima facie principles remain at the centre of education and debate in bioethics: beneficence, nonmaleficence, respect for persons, and justice. They provide the source of rules for ethical decisions (for example, truth telling, privacy, informed consent, etc). Rules are not deduced from principles (that is, principlism) but rather arise from specification. Users of casuistry may also refer to principles when selecting maxims.
  • Principlism
    • MeSH - Wikipedia
      Principlism is a system of ethics based on the four moral principles of beneficence, nonmaleficence, respect for persons, and justice.
      An approach to ethics that focuses on theories of the importance of general principles such as respect for autonomy, beneficence/nonmaleficence, and justice.
      Also called principle-based ethics.
  • Prior probability
    • Wikipedia
      The probability of an event before new evidence. Bayes's rule specifies how prior probabilities are updated in the light of new evidence.
  • Priority diseases
    • Diseases/conditions that have been identified to be of important/major public health concern.
  • Priority setting/rationing
    • Rationing is an unavoidable consequence of scarcity. If there are not sufficient resources to meet all “needs” then some needs must be left unmet and priority should be given to services that best meet one's objectives. Priority setting refers to the process of deciding which needs should be met and which needs cannot be met, at least not immediately.
  • Privacy
    • MeSH - Wikipedia
      What a person claims as protected from scrutiny by others unless the person chooses to reveal it. Respect for privacy means that a person should not normally be expected to reveal personal information, conditions, or behavior unless he/she chooses to reveal it. Violation of privacy requires ethical justification, for example, in cases where it is argued such violations protect others from greater harm.
      The state of being free from intrusion or disturbance in one's private life or affairs.
  • Private practice
    • MeSH
      Practice of a health profession by an individual, offering services on a person-to-person basis, as opposed to group or partnership practice.
  • Probabilistic cause
    • A probabilistic cause is one that increases or decreases the chance (likelihood) that the effect will occur.cur.
  • Probability
    • MeSH - Wikipedia
      The chance or likelihood of an event happening. Probability may vary in value from 0 (no chance) to 1 (certain). Researchers have to set the level of probability/certainty they are willing to accept for their findings.
      The study of chance processes or the relative frequency characterizing a chance process.
  • Probability distribution
    • Wikipedia
      The function that gives the probabilities that a variable equals each of a sequence of possible values. Examples include the binomial distribution, normal distribution and Poisson distribution.
  • Probability sampling
    • All individuals have a known chance of selection. They may all have an equal chance of being selected, or, if a stratified sampling method is used, the rate at which individuals from several subsets are sampled can be varied so as to produce greater representation of some classes than of others. A probability sample is created by assigning an identity (label, number) to all individuals in the “universe” population, e.g., by arranging them in alphabetical order and numbering in sequence, or simply assigning a number to each, or by grouping according to area of residence and numbering the groups. The next step is to select individuals (or groups) for study by a procedure such as use of a table of random numbers (or comparable procedure) to ensure that the chance of selection is known.
  • Probability theory
    • MeSH - Wikipedia
      The branch of mathematics concerned with analysis of random phenomena.
      The branch of mathematics dealing with the purely logical properties of probability. Its theorems underlie most statistical methods.
  • Process assessment (health care)
    • MeSH
      An evaluation procedure that focuses on how care is delivered, based on the premise that there are standards of performance for activities undertaken in delivering patient care, in which the specific actions taken, events occurring, and human interactions are compared with accepted standards.
  • Process evaluation
    • Process evaluation assesses the implementation of the intervention and its effects on the various participants. It questions how the intervention took place, whether it was performed in conformity with its design, and whether the designated target group was reached. The process evaluation will help to explain outcome data and to discuss improvement of the intervention in the future.
      Process evaluation sets out to evaluate how successful the process of carrying out the health impact assessment was in practice. It is important as a source of learning, for quality improvement, and as a mechanism of quality assurance.
  • Process indicator
    • Process indicators relate the outputs of a project (its deliverables, structures created, opportunities given, materials published) to its operational objectives.
  • Processes of health care
    • Aspects of the behavior or performance of the health care system or health facility and the nature of participation on the part of people its serves. These consist of two parts: behaviors of the professionals and participation of the people who relate to the system or facility. Behaviors of professionals include the spectrum of clinical care involving problem (or needs) recognition, the diagnostic process, the recommendation of treatment or management; and appropriate follow up. Participation of people who relate to the system includes utilization; understanding of recommendations, satisfaction with services rendered, and participation in decisions concerning strategies for management.
  • Product line management
    • MeSH
      Management control systems for structuring health care delivery strategies around case types, as in DRGs, or specific clinical services.
  • Professional ethics
    • MeSH - Wikipedia
      Professional ethics concerns the moral issues that arise because of the specialist knowledge that professionals attain, and how the use of this knowledge should be governed when providing a service to the public.
      The principles of proper conduct concerning the rights and duties of the professional, relations with patients or consumers and fellow practitioners, as well as actions of the professional and interpersonal relations with patient or consumer families.
  • Professional ethics guidelines
    • Documents prepared by members of a public health discipline or representative professional society containing core values, duties (obligations), and virtues of the profession, sometimes in the form of general principles. Distinguished from guidelines for good scientific practices and from rules of professional etiquette, ethics guidelines are consensus documents, providing a foundation for discussion of issues arising in practice such as minimizing risks and protecting the welfare of research participants, maintaining public trust, protecting confidentiality and privacy, and obligations to communities.
  • Professional misconduct
    • MeSH
    • Violation of laws, regulations, or professional standards.
  • Professional nurses ratio
    • The number of certified nurses available per every 10,000 inhabitants in a population, at a given year, for a given country, territory, or geographic area. Certified nurses not includes auxiliary and unlicensed personnel.
  • Prognosis
    • MeSH - Wikipedia
      The possible consequences and outcomes of a disease and the frequency with which they can be expected to occur.
      A prediction of the probable outcome of a disease based on a individual's condition and the usual course of the disease as seen in similar situations.
  • Prognostic factors
    • Patient or study participant characteristics that confer increased or decreased risk of a positive or adverse outcome.
  • Prognostic study
    • A study that enrolls patients at a point in time and follows them forward to determine the frequency and timing of subsequent events.
  • Prognostic variable
    • A baseline variable that is prognostic in the absence of intervention Unrestricted, simple randomization can lead to chance baseline imbalance in prognostic variables, which can affect the results and weaken the trial's credibility. Stratification and minimization protect against such imbalances.
  • Program
    • A program is a series of related activities that give effect to policy.
  • Program development
    • MeSH
      The process of formulating, improving, and expanding educational, managerial, or service-oriented work plans (excluding computer program development).
  • Program evaluation
    • MeSH - Wikipedia
      A systematic method for collecting, analyzing, and using information to answer basic questions about projects, policies and programs.
      Studies designed to assess the efficacy of programs. They may include the evaluation of cost-effectiveness, the extent to which objectives are met, or impact.
  • Project
    • A project is a component of a program, and is a discrete activity often undertaken at a specific location.
  • Prolonged pregnancy
    • MeSH
      A term used to describe pregnancies that exceed the upper limit of a normal gestational period. In humans, a prolonged pregnancy is defined as one that extends beyond 42 weeks (294 days) after the first day of the last menstrual period (menstruation), or birth with gestational age of 41 weeks or more.
  • Propensity score
    • MeSH - Wikipedia
      In the design of experiments, a propensity score is the probability of a unit (e.g., person, classroom, school) being assigned to a particular condition in a study given a set of known covariates.
      Conditional probability of exposure to a treatment given observed covariates.
  • Proportion
    • Wikipedia
      The ratio of one value to another expressed as a fraction of one. For example, the proportion of women among patients with cardiovascular disease.
      A type of ratio in which the numerator is included in the denominator. The ratio of a part to the whole, expressed as a "decimal fraction'' (e.g., 0.2), as a fraction (1/5), or, loosely, as a percentage (20%).
  • Proportion of deliveries attended by trained personnel
    • The number of deliveries assisted by trained personnel in a specific year, regardless of their site of ocurrence, expressed as a percentage of the total number of births in that same year, in a given country, territory, or geographic area. Trained staff includes medical obstetricians, physicians with training in delivery care, university midwives and nurses with training in delivery care and graduated midwives; it does not include traditional midwives trained or not.
  • Proportion of population below the international poverty line
    • The percentage of the population living below the international poverty line in a given country, territory, or geographic area, for a given sex and/or age group, at a specific period in time, usually a year. International poverty line is defined at less than US$1.08 a day at 1993 international prices, equivalent to US$1 in 1985 international prices, adjusted to local currency using purchasing power parities.
  • Proportion of population below the national poverty line
    • The percentage of the population living below the national poverty line in a given country, territory, or geographic area, at a specific period in time, usually a year. The operational definition for a national poverty line varies from country to country and represents the amount of income required by each household to meet the basic needs of all its members.
  • Proportion of pregnant women attended by trained personnel during pregnancy
    • The number of pregnant women who have received at least one health care visit during pregnancy provided by a trained health worker, expressed as a percentage of the live birth population, at a given year, for a given country, territory, or geographic area. Health care visit during pregnancy is defined as those health care services for the control and monitoring of the pregnancy and ambulatory care for associated morbidity; it does not include neither direct vaccination activities nor the health care services rendered immediately prior to delivery. Trained staff includes medical obstetricians, physicians with training in delivery care, university midwives and nurses with training in delivery care and graduated midwives; it does not include traditional midwives trained or not.
  • Proportion of urban population
    • The percentage of total population of a country, territory, or geographic area living in places defined as urban, at a specific point of time, usually mid-year. The term urban refers essentially to cities, towns, and other densely populated areas. The demarcation of urban areas is usually defined by countries as part of census procedures, and is usually based on the size of localities, and/or the classification of areas as administrative centers or in accordance to special criteria such as population density or type of economic activity of residents. There is no international agreed definition of urban areas, and national operational definitions may vary from country to country.
  • Proportional hazards model
    • MeSH - Wikipedia
      In survival analysis: a statistical model that asserts that the effect of the study factors (e.g. the intervention of interest) on the hazard rate (the risk of occurrence of an event, such as death, at a point in time) in the study population is multiplicative and does not change over time. (Also called Cox model.)
      Statistical models used in survival analysis that assert that the effect of the study factors on the hazard rate in the study population is multiplicative and does not change over time.
  • Proportionate mortality
    • Fraction of all deaths due to a specific cause.
      The proportion of deaths in a specified population over a period of time attributable to different causes. Each cause is expressed as a percentage of all deaths, and the sum of the causes must add to 100%. These proportions are not mortality rates, since the denominator is all deaths, not the population in which the deaths occurred.
  • Proposal
    • A document written for the purpose of obtaining funding for a research project.
  • Prospective
    • Wikipedia
      In medicine, a study or clinical trial in which participants are identified and then followed forward in time.
  • Prospective cohort study
    • Wikipedia
      A research study that follows over time groups of individuals who are alike in many ways but differ by a certain characteristic (for example, female nurses who smoke and those who do not smoke) and compares them for a particular outcome.
  • Prospective study
    • MeSH - Wikipedia
      In evaluations of the effects of healthcare interventions, a study in which people are identified according to current risk status or exposure, and followed forwards through time to observe outcome. Randomized controlled trials are always prospective studies. Cohort studies are commonly either prospective or retrospective, whereas case-control studies are usually retrospective. In Epidemiology, 'prospective study’ is sometimes misused as a synonym for cohort study.
      A study in which events or cases are observed or studied as they occur, or in which human subjects are identified and followed forward in time.
      Observation of a population for a sufficient number of persons over a sufficient number of years to generate incidence or mortality rates subsequent to the selection of the study group.
  • Prospective surveillance
    • Ongoing collection of epidemiological data, with real-time analysis. Mortality surveillance systems usually rely on home visitors who record deaths in households on a weekly basis.
  • Protocol
    • Wikipedia
      The plan or set of steps to be followed in a study. A protocol for a systematic review should describe the rationale for the review, the objectives, and the methods that will be used to locate, select, and critically appraise studies, and to collect and analyze data from the included studies.
      Protocol is a set of directions or rules regarding a sequence of activities in a specified situation or setting. The directions are formulated in advance and are recorded in some way. The purpose of a protocol is to give a general structure for the activities and by doing so to help collaboration between persons, organizations and societies.
      In terms of health technology assessment (HTA), a protocol is a detailed plan that, by providing a list of steps or procedures, guides the development of a full HTA report. A protocol usually contains an introduction, the objectives of the report, the methodology to be followed (e.g. inclusion criteria for clinical trials, methodology of data extraction and analysis), the role of each person involved in the process, a detailed search strategy and the time frame for all stages of the developing full HTA process. The objective of a protocol is to inform all stakeholders and other HTA agencies about the undertaken HTA report and avoid unnecessary doubling of the work. A protocol also enables a reviewer to verify whether the whole process has been carried out properly and, if yes, it enables others to update the search on the topic in question by using the search strategy determined in the protocol.
  • Protocol amendment
    • A written description of a change(s) to or formal clarification of a protocol.
  • Protocol deviation
    • A failure to adhere to the pre-specified trial protocol, or a participant for whom this occurred. Examples are participants found to have been included in the trial by mistake (they were ineligible) and those for whom the intervention or other procedure differed from that outlined in the protocol.
  • Provider adherence
    • Extent that health care providers carry out the host of diagnostic tests, monitoring equipment, interventional requirements, and other technical specifications that define optimal patient management.
  • Psychosocial intervention
    • Psychosocial interventions include structured counseling, motivational enhancement, case management, care-coordination, psychotherapy and relapse prevention.
  • Puberty
    • MeSH
      A period in the human life in which the development of the hypothalamic-pituitary-gonadal system takes place and reaches full maturity. The onset of synchronized endocrine events in puberty lead to the capacity for reproduction (fertility), development of secondary sex characteristics, and other changes seen in adolescent development.
  • Public health
    • MeSH - Wikipedia
      The science and art of promoting health, preventing disease, and prolonging life through the organized efforts of society.
      Public health is the science and art of preventing disease, prolonging life and promoting health through the organized efforts and informed choices of society, organizations, public and private, communities and individuals.
      Public health refers to all organized measures (whether public or private) to prevent disease, promote health, and prolong life among the population as a whole.
      Branch of medicine concerned with the prevention and control of disease and disability, and the promotion of physical and mental health of the population on the international, national, state, or municipal level.
  • Public health administration
    • MeSH
      Management of public health organizations or agencies.
  • Public health care sector
    • Refers to public finance and provision of health care services.
  • Public health emergency
    • A public health emergency (the condition that requires the governor to declare a state of public health emergency) is defined as "an occurrence or imminent threat of an illness or health condition, caused by bio terrorism, epidemic or pandemic disease, or (a) novel and highly fatal infectious agent or biological toxin, that poses a substantial risk of a significant number of human facilities or incidents or permanent or long-term disability. The declaration of a state of public health emergency permits the governor to suspend state regulations, change the functions of state agencies.
  • Public health informatics
    • MeSH - Wikipedia
      The systematic application of information and computer sciences to public health practice, research, and learning.
  • Public health intervention
    • A public health intervention can be defined by the fact that it is applied to many, most, or all members in a community, with the aim of delivering a net benefit to the community or population as well as benefits to individuals. Public health interventions include policies of governments and non-government organizations; laws and regulations; organizational development; community development; education of individuals and communities; engineering and technical developments; service development and delivery; and communication, including social marketing.
  • Public health law
    • Wikipedia
      Public health law focuses on legal issues in public health practice and on the public health effects of legal practice. Public health law typically has three major areas of practice: police power, disease and injury prevention, and the law of populations.
  • Public health nursing
    • MeSH
      The field of nursing focusing on the health of the community through educational and preventive programs, as well as providing treatment and diagnostic services.
  • Public health practice
    • MeSH
      The activities and endeavors of the public health services in a community on any level.
  • Public health surveillance
    • The systematic collection, analysis, interpretation, and dissemination of health data on an ongoing basis, to gain knowledge of the pattern of disease occurrence and potential in a community, in order to control and prevent disease in the community.
  • Public policy
    • MeSH - Wikipedia
      Public policy can be generally defined as the course of action or inaction taken by governmental entities (the decisions of government) with regard to a particular issue or set of issues.
      A course or method of action selected, usually by a government, from among alternatives to guide and determine present and future decisions.
  • Publication bias
    • MeSH - Wikipedia
      Occurs when the publication of research depends on the direction of the study results and whether they are statistically significant.
      Publication bias is the bias that can result in a systematic review because studies with statistically significant results are more likely to be published than those that show no effect (particularly for intervention studies). Publication bias can be minimized if an attempt is made to include in a systematic review all relevant published and unpublished studies. This process can be facilitated by international registers of trials.
      Bias produced when the published studies do not represent adequately all the studies carried out on a specific topic. Many facts can origin this bias, although the best known is the trend to publish statistically significant (p < 0.05) or clinically relevant (high magnitude albeit non-significant) results. Other variables influencing publication bias are sample size (more in small studies), type of design (less in well conducted randomized controlled trials), funding, conflict of interest, prejudice against an observed association (for example, cocaine consumption and non-adverse effect on fetus), sponsorship.
      The influence of study results on the chances of publication and the tendency of investigators, reviewers, and editors to submit or accept manuscripts for publication based on the direction or strength of the study findings. Publication bias has an impact on the interpretation of clinical trials and meta-analyses. Bias can be minimized by insistence by editors on high-quality research, thorough literature reviews, acknowledgement of conflicts of interest, modification of peer review practices, etc.
  • Published erratum
    • Published erratum [MeSH - publication type]: work consisting of an acknowledgment of an error, issued by a publisher, editor, or author. It customarily cites the source where the error occurred, giving complete bibliographic data for retrieval. In the case of books and monographs, author, title, imprint, paging, and other helpful references will be given; in the case of journal articles, the author, title, paging, and journal reference will be shown. An erratum notice is variously cited as Errata or Corrigenda.
  • Purposeful sampling
    • In qualitative research, a type of nonprobability sampling in which theory or personal judgment guide the selection of study participants who will be most representative of the population. Depending on the topic, examples include (1) maximum variation sampling, to document range or diversity; (2) extreme or deviant case sampling, in which one selects cases that are opposite in some way; (3) typical or representative case sampling, to describe and illustrate what is typical and common in terms of the phenomenon of interest; (4) critical sampling, to make a point dramatically; and (5) criterion sampling, in which all cases that meet some predetermined criteria of importance are studied.