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GLOSSARY
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## Terms used in therapeutics

Allocation concealed: the study adequately conceals study group allocation from those responsible for assessing participants at trial entry.

Allocation not concealed: study group allocation was known to those assessing participants for entry in the trial.

Unclear allocation concealment: the article does not contain a full description of how participants were allocated.

Blinded (or masked'): clinicians, participants, outcome assessors or statisticians were not told who received the treatment or control interventions. In abstracts, those blinded are explicitly indicated.

Unblinded: clinicians, participants, outcome assessors and statisticians knew how interventions and controls were allocated.

## Terms used in systematic reviews

Heterogeneity: occurs when there is more variation between the study results than would be expected by chance alone. In the presence of heterogeneous results, a random effects pooled odds ratio is usually preferred over a fixed effects pooled odds ratio.

Odds ratio (OR): the odds' of an event is the ratio of the chance of it occurring to the chance of it not occurring. The odds ratio is a measure of the relative benefit of the experimental treatment, comparing the odds of an event in the intervention group to the odds of an event in the control group.

## Terms used in diagnosis

Sensitivity: the sensitivity of a test is the proportion of people with the condition of interest who test positive (according to the diagnostic gold standard).

Specificity: the proportion of people who do not have the condition of interest who test negative (according to the diagnostic gold standard).

Likelihood ratio for a positive test result/positive predictive value: the likelihood that a positive test comes from a person with the condition of interest rather than one without the disorder.

Likelihood ratio for a negative test result/negative predictive value: the likelihood that a negative test comes from a person with the condition of interest rather than someone without the disorder.

## Terms used when presenting data

ABI (absolute benefit increase)/ARR (absolute risk reduction) /ARI (absolute risk increase): the absolute arithmetic difference in rates of an outcome between the intervention and control groups.

NNT (number needed to treat)/NNH (number needed to harm): the number of people who need to receive the experimental treatment to create one additional improved outcome (NNT) or one additional harmful outcome (calculated as 1/ARR). The lower the NNT, the more effective the intervention.

RBI (relative benefit increase)/RRR (relative risk reduction)/ RRI (relative risk increase): the proportional increase or decrease in events between the intervention and control groups. RRI relates to negative or harmful events.

Confidence interval (CI): the range of values within which the true value for the population is expected to lie with a given degree of certainty (usually reported as 95% CI).

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