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A priori

In clinical trial design, this distinguishes something that is done before the study is started. Determining specific study criteria prior to study initiation.

Absolute risk reduction

The difference in the percentage of subjects developing the adverse event in the control group versus subjects in the intervention group. Also refers to the number of subjects spared the adverse event by taking the intervention compared to the control.

Abstracting service

A database that provides abstracts and citations for journal articles.


A synopsis (usually of 250 words or less) of the most important aspect(s) of an article.


Pertaining to a college, school, or other educational institution.

Academic detailing

A process by which a health care educator visits a physician to provide a 15- to 20-minute educational intervention on a specific topic. Information provided is based on the physician's prescribing patterns and evidence-based medicine to improve prescribing.

Accountable care organization

A collaborative group of hospitals, doctors, and other providers of health care who coordinate their patient care efforts for Medicare patients. An emphasis is placed on minimizing duplication of effort and preventing medical errors, in particular, for the chronically ill.


A term coined by Beauchamp and Childress to refer to a hierarchical approach to analysis of an ethical issue when forming particular judgments about the issue.

Active control

A standard therapy or procedure (but not a placebo) used in a study to determine the difference in effect produced by the study intervention.

Adaptive clinical trial

A trial design, also known as group sequential design, that allows adaptation of various components such as inclusion/exclusion criteria, dosing, efficacy outcomes, and duration of trial based on continuously emerging knowledge throughout the study.

Adjunctive therapy

A therapy (e.g., medication, exercise, diet) that all subjects within a study receive. Since all subjects are receiving, it is not considered a study bias since the effect of this therapy occurs among all subjects within the study.

Adverse drug event (ADE)

An ADE is defined as an injury from a medicine or lack of intended medicine. An ADE refers to all adverse drug reactions (ADRs), including allergic or idiosyncratic reactions, as well as medication errors that result in harm to a patient.

Adverse drug event (ADE) monitoring

Computer programs that use electronic data and predetermined rules to identify when an ADE may have occurred or is about to occur.

Adverse drug event (ADE) trigger tool

It is an augmented chart review method that uses automated systems to identify alerts or triggers to efficiently identify patients with potential ADEs. The triggers are cues that a patient may have experienced an error and/or adverse event. When these triggers are identified, it is suspected that the patient may have experienced a medication error. The patient's chart is reviewed for evidence of error and/or level of harm and data are collected and collated to determine potential common causes.

Adverse drug reaction (ADR)

Defined broadly, any unexpected, unintended, undesired, or excessive response to a medicine. The Food and Drug Administration's ...

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