MMDC Medical Licensing Exam key terms

The proportion of people who truly have a disease and are correctly identified as having it by a test. It measures how well a test detects disease when disease is present.

The proportion of people who do not have a disease and are correctly identified as disease-free by a test. It measures how well a test rules out disease in healthy people.

The probability that a person with a positive test result actually has the disease. It depends on both test accuracy and how common the disease is in the population tested.

The probability that a person with a negative test result truly does not have the disease. Like positive predictive value, it changes with the prevalence of the condition in the tested group.

The total number of existing cases of a disease in a population at a given time, divided by the population size. It reflects how widespread a condition is and influences predictive values of tests.

The number of new cases of a disease arising in a population over a defined period, divided by the population at risk. It measures how rapidly new disease is occurring.

The ratio of disease incidence in an exposed group to incidence in an unexposed group. A value above one suggests the exposure increases risk of the outcome.

The ratio of the odds of exposure among people with a disease to the odds of exposure among those without it. It is commonly used to estimate association in case-control studies.

The number of patients who must receive a treatment for one additional patient to benefit. It is the reciprocal of the absolute risk reduction and expresses treatment efficiency.

The arithmetic difference in event rates between a control group and a treated group. It shows the actual drop in risk attributable to the intervention, unlike relative measures.

A range of values, calculated from sample data, that is likely to contain the true population value with a stated probability. It conveys both the estimate and its precision.

The probability of observing a result at least as extreme as the study finding if the null hypothesis were true. It indicates statistical significance but not the size of an effect.

The default assumption that there is no difference or no association between the variables being studied. Statistical tests assess how compatible observed data are with this assumption.

Incorrectly rejecting a true null hypothesis, that is, finding a difference when none truly exists. Its probability is denoted alpha, conventionally set at 0.05.

Failing to reject a false null hypothesis, that is, missing a real difference. Its probability is denoted beta, and one minus beta equals the study's statistical power.

The probability that a study will detect a true effect of a given size if it exists. It is calculated as one minus the type II error rate and is increased by larger samples.

An experiment in which participants are randomly assigned to intervention or control groups. Randomization balances known and unknown confounders, supporting causal inference about treatment effects.

An observational design that compares people with a disease to similar people without it and looks back at prior exposures. It is efficient for rare diseases but vulnerable to recall bias.

An observational design that follows groups defined by exposure status over time and compares the incidence of outcomes. It can establish temporal sequence but is costly and prone to loss to follow-up.

A distortion of the exposure-outcome relationship caused by a third variable that is associated with both. It can create or mask an apparent association if not controlled by design or analysis.

A systematic error that arises when the groups compared differ in ways related to the outcome because of how participants were chosen or retained. It compromises the validity of comparisons.

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

Apparent improvement in survival caused by earlier detection of disease rather than by delayed death. Screening that advances diagnosis without changing outcome can falsely appear beneficial.

The tendency of screening programs to preferentially detect slowly progressive disease, which has a better prognosis regardless of treatment. It can exaggerate the apparent benefit of screening.

The systematic testing of apparently healthy people to detect unrecognized disease at an early, more treatable stage. It requires a suitable test, an effective treatment, and acceptable harms and costs.

The practice of concealing treatment allocation from participants, clinicians, or assessors to prevent expectations from influencing results. It reduces performance and detection bias in trials.

An analysis that includes all randomized participants in the groups to which they were assigned, regardless of adherence. It preserves the benefits of randomization and reflects real-world effectiveness.

A pre-study determination of how many participants are needed to detect a specified effect with adequate power and acceptable error rates. It depends on effect size, variability, alpha, and power.

A patient's voluntary agreement to a test or treatment after receiving and understanding information about its nature, benefits, risks, and alternatives. It requires decision-making capacity and freedom from coercion.

A patient's ability to understand relevant information, appreciate the consequences of choices, reason through options, and communicate a consistent decision. It is assessed for a specific decision rather than globally.

A minor's or cognitively limited person's agreement to participate in care or research, obtained alongside permission from a surrogate. It respects developing autonomy even when legal consent rests elsewhere.

A written statement, made while a person has capacity, specifying preferences for future medical care or naming a surrogate decision-maker. It guides treatment when the patient can no longer express wishes.

The professional duty to protect patient information from unauthorized disclosure. It may be overridden only in specific situations defined by law, such as reportable diseases or imminent serious harm.

A legal obligation for clinicians to notify authorities about specified conditions or events, such as certain communicable diseases, child abuse, or impaired driving. It is an exception to usual confidentiality.

A clinical judgment that an intervention cannot achieve its intended physiological goal or provide meaningful benefit. It is often invoked in end-of-life decisions but remains ethically and legally contested.

A condition that clinicians and laboratories are legally required to report to public health authorities. Reporting enables surveillance, outbreak investigation, and control measures for the community.

The ongoing systematic collection, analysis, and interpretation of health data for planning and evaluating public health practice. It underpins outbreak detection, trend monitoring, and resource allocation.

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