Confounding by indication A distortion that modifies an association between an exposure and an outcome, caused by the presence of an indication for the exposure that is the true cause of the outcome. Read More
Data-dredging bias A distortion that arises from presenting the results of unplanned statistical tests as if they were a fully prespecified course of analyses. Read More
Diagnostic access bias Individuals differ in their geographic, temporal and economic access to diagnostic procedures which label them as having a given disease. Read More
Diagnostic suspicion bias Knowledge of a subject’s prior exposures or personal biases may influence both the process and the outcome of diagnostic tests. Read More
Differential Reference bias When not all participants receive the same reference test in a diagnostic accuracy study. Read More
Early Stopping Bias A distortion of treatment effect estimates that arises when a clinical trial is stopped early, whether for benefit, futility, or safety, following an interim analysis. Read More
Hawthorne effect When individuals modify an aspect of their behaviour in response to their awareness of being observed. Read More
Hot stuff bias When a topic is fashionable (‘hot’) investigators may be less critical in their approach to their research, and investigators and editors may not be able to resist the temptation to publish the results. Read More
Hypothetical bias A distortion that arises when an individual’s stated behaviour or valuation differs to that of their real behaviour or valuation. Read More
Immortal time bias A distortion that modifies an association between an exposure and an outcome, caused when a cohort study is designed so that follow-up includes a period of time where participants in the exposed group cannot experience the outcome and are essentially ‘immortal’. Read More
Incorporation bias When the results of an index test form part of the reference test in a diagnostic study. Read More
Industry Sponsorship bias A tendency for the methods and results of a study to support the interests of the funding organisation. Read More
Information bias Bias that arises from systematic differences in the collection, recall, recording or handling of information used in a study. Read More
Informed presence bias The presence of a person’s information in an electronic health record is affected by the person’s health status. Read More
