Emerging Wellness Science Glossary

How to use this glossary

These are the terms that come up again and again in emerging health research. Each entry is short and in plain words. Where a term is used differently by different groups, the entry says whose definition we follow. Terms are in alphabetical order. A definition is not a judgment about any product.

Biomarker

A measurable sign in the body, found in blood, other fluids or tissues, that points to a normal or abnormal process or to a condition. [3] FDA describes it as a defined characteristic that is objectively measured as an indicator of normal biological processes, pathologic processes, or responses. [4] A biomarker is not the same as how a person feels or lives. See Biomarkers vs Clinical Outcomes.

Blinding

A design in which participants, or participants and their doctors, do not know which treatment is being given. [5] It limits the way expectations can shape results. See Randomization, Blinding and Placebo.

Clinical endpoint

An event or outcome measured objectively to decide whether the intervention being studied is beneficial. [6] Clinical outcomes directly measure whether people in a trial feel or function better, or live longer. [4] Compare with surrogate endpoint.

Clinical utility

Whether using a test leads, through an action taken because of the result, to a better health outcome. In the NCI genetics dictionary it is the likelihood that a test will, by prompting an intervention, result in an improved health outcome. [7] A test can be accurate and still lack clinical utility.

Confidence interval

A range that shows how uncertain an estimate is. [2] A narrow interval means the effect size is known fairly precisely, a wide one means more uncertainty. [2]

Effect size

How big a difference is. The point estimate is the best estimate of the magnitude and direction of an intervention's effect compared with the comparator. [2] Different scales can be combined into a standardized mean difference. [2] Always read the effect size with its confidence interval.

Investigational

A drug or procedure being tested in people. It may be approved for one condition and still be investigational for another. [8] Investigational does not mean safe or effective, and it does not mean unapproved everywhere.

Mechanism

How a drug or other substance produces an effect in the body, such as acting on a particular target in a cell. [9] A plausible mechanism is a reason to run a study. It is not a result. See The Translational Pipeline From Laboratory to Approval.

Off-label

Use of an approved drug in a way it is not approved for, such as a different condition. [10] Prescribers generally may do this when they judge it medically appropriate, but FDA has not determined that the drug is safe and effective for the unapproved use. [10]

Placebo

An inactive substance or other intervention that looks the same as, and is given the same way as, the treatment being tested. [11] It lets researchers compare the real treatment with something that feels the same.

Preprint

A complete and public draft of a scientific document that is not yet certified by peer review. [12] Results and conclusions may change after review. [12]

Randomization

Assigning participants by chance to separate groups given different treatments, so that neither researcher nor participant chooses. [13] This makes the comparison fairer.

Replication

Repeating a study to see whether the finding holds. Replication effects can be smaller: in one large project in psychology, they were half the magnitude of the original effects. [17] One result is a starting point, not a settled fact.

Surrogate endpoint

A stand-in for a direct measure of how a patient feels, functions or survives. [4] Surrogate endpoints are not always true indicators of how well a treatment works. [18] Candidate surrogate endpoints are still under evaluation for their ability to predict clinical benefit. [4]

Translational research

The process by which laboratory results are used to develop new ways to diagnose and treat disease. [19] NCATS describes translation as turning observations in the laboratory, clinic and community into interventions that improve health. [20]

Where to read more

For how we use these terms in summaries, see How We Write Study Explainers and Research Updates. For the labels we attach to evidence, see How We Label Evidence in Specialty Topics.