ABPM Public Health key terms

The number of new cases of a disease that develop in a defined population during a specified time period, divided by the person-time at risk. It measures how quickly new cases arise.

The proportion of a population that has a disease or condition at a given point in time (point prevalence) or during a period (period prevalence). It reflects total existing burden rather than speed of new occurrence.

The sum of time each individual in a cohort remains under observation and at risk, often expressed as person-years. It forms the denominator for incidence rates when follow-up length varies across people.

The proportion of an exposed group that becomes ill during a limited outbreak period. It is a type of incidence proportion used to characterize rapidly spreading events such as foodborne illness.

The proportion of people diagnosed with a disease who die from it within a specified period. It describes severity of disease among cases rather than risk in the whole population.

The number of deaths in a population during a period divided by the population size, usually scaled per 1,000 or 100,000. Crude rates can be adjusted for age to allow fair comparison.

A statistical technique that applies a study population's age-specific rates to a standard age distribution, removing the effect of age differences so rates from different populations can be compared fairly.

The ratio of disease risk in an exposed group to risk in an unexposed group. A value of 1.0 indicates no association; values above or below suggest increased or decreased risk.

The ratio of the odds of exposure among cases to the odds of exposure among controls. It approximates relative risk when the disease is rare and is the standard measure in case-control studies.

An observational design that follows groups defined by exposure status over time and compares disease occurrence between them. Because exposure precedes outcome, it supports stronger causal inference than case-control designs.

An observational design that selects people with a disease (cases) and comparable people without it (controls), then compares past exposure histories. It is efficient for rare outcomes but vulnerable to recall bias.

A study that measures exposure and outcome simultaneously in a population at one point in time. It estimates prevalence but generally cannot establish whether exposure preceded disease.

An observational design in which the unit of analysis is a group rather than an individual, comparing aggregate rates across populations. Findings may not apply to individuals, a problem called ecological fallacy.

An error in reasoning where an association observed between group-level variables is assumed to hold at the individual level. Aggregate data cannot reveal individual-level relationships.

An experimental study in which participants are randomly assigned to intervention or control groups. Randomization balances known and unknown confounders, making it the strongest design for testing causal effects.

Distortion of an exposure-outcome association by a third variable that is associated with both and is not on the causal pathway. It can create, exaggerate, or mask a true relationship.

A situation in which the magnitude of an exposure's effect on an outcome differs across levels of a third variable, such as age or sex. Unlike confounding, it is a real biological or social phenomenon to report.

Systematic error that arises when the people included in a study differ from those eligible in ways related to both exposure and outcome. It can distort measures of association in any study design.

A systematic error in which people with a disease remember or report past exposures differently from people without it. It is a particular threat in retrospective case-control studies.

The proportion of people who truly have a condition that a screening or diagnostic test correctly identifies as positive. High sensitivity means few false negatives.

The proportion of people who truly do not have a condition that a test correctly identifies as negative. High specificity means few false positives and supports confirmation of a diagnosis.

The probability that a person with a positive test result actually has the condition. It depends on disease prevalence in the tested population as well as test sensitivity and specificity.

Apparent improvement in survival that results only from earlier detection of disease rather than from delayed death. Screening programs can appear beneficial when they merely shift the diagnosis date earlier.

The tendency of screening to detect slowly progressing disease disproportionately, because such cases remain detectable longer. This makes screened groups look like they survive longer even without true benefit.

A method for adjusting summary rates to remove the influence of a differing characteristic, usually age, so populations can be compared. Direct and indirect methods use a standard population's weights.

A range of values calculated from sample data that is likely to contain the true population parameter with a stated probability, commonly 95 percent. Its width reflects precision of the estimate.

The probability of observing a result at least as extreme as the one obtained, assuming the null hypothesis is true. It is not the probability that the null hypothesis is correct.

The probability that a study will detect a true effect of a given size, equal to 1 minus the type II error rate. Underpowered studies may miss real associations.

The number of participants a study must enroll to achieve adequate precision and power. It depends on expected effect size, variability, significance level, and desired power.

The standard deviation of a statistic's sampling distribution, estimating how much a sample estimate varies from sample to sample. It is used to build confidence intervals around estimates.

An analysis that includes all randomized participants in the groups to which they were assigned, regardless of adherence. It preserves randomization benefits and gives a conservative estimate of effectiveness.

Indirect protection of unvaccinated people that occurs when a sufficiently high proportion of a population is immune, reducing transmission. The threshold depends on how contagious the pathogen is.

A structured public health response to excess cases of a disease, involving case finding, hypothesis generation, analytic studies, and control measures. It aims to identify the source and stop transmission.

The ongoing, systematic collection, analysis, and interpretation of health data used to plan, implement, and evaluate public health practice. It enables early detection of trends and outbreaks.

A legal requirement for clinicians and laboratories to report specified diagnoses to public health authorities. These reports feed surveillance systems that guide disease control efforts.

Measures taken before disease occurs to reduce risk in susceptible people, such as immunization, fluoridation, or health education. It aims to prevent the onset of illness entirely.

Early detection and prompt treatment of disease at a presymptomatic stage to halt progression, as with screening programs. It improves outcomes by intervening before clinical disease becomes advanced.

Rehabilitation and treatment that reduce disability and complications after disease has occurred. It focuses on restoring function and limiting the long-term impact of established illness.

The planning, organizing, directing, and controlling of resources to deliver health care and public health services. It balances access, quality, cost, and population needs.

The range of personal, social, economic, and environmental factors that influence health status. They include income, education, physical environment, and access to care.

Conditions in the environments where people are born, live, learn, work, and age that shape health outcomes. They include income, housing, education, and neighborhood safety.

A preventable difference in health status or access to care that is closely linked to social or economic disadvantage. It often reflects systemic inequities rather than biological variation.

A behavioral theory proposing that health action depends on perceived susceptibility, severity, benefits, and barriers, plus cues to action and self-efficacy. It is widely used to design health education interventions.

A behavior change framework describing progression through precontemplation, contemplation, preparation, action, and maintenance. Interventions are matched to a person's current stage of readiness.

The systematic process of identifying hazards, characterizing exposure, and estimating the likelihood and severity of harm to human health or the environment. It informs risk management decisions.

The measurement or estimation of how, how much, how long, and how often people contact a hazardous agent. It is a critical step in environmental risk assessment and epidemiology.

The observed association between increasing levels of an exposure and increasing likelihood or severity of a health effect. Its presence strengthens causal inference in environmental and occupational studies.

The science of adverse effects of chemical, physical, or biological agents on living organisms. It uses animal and in vitro studies to characterize hazards and safe exposure levels.

An unexpected occurrence involving death or serious harm that signals the need for immediate investigation and response. In health care it often triggers root cause analysis.