Biases

Positive results bias

The tendency to submit, accept and publish positive results rather than non-significant or negative results.

Prevalence-incidence (Neyman) bias

Exclusion of individuals with severe or mild disease resulting in a systematic error in the estimated association or effect of an exposure on an outcome.

Previous opinion bias

The results of a previous assessment, test result or diagnosis, if known, may affect the results of subsequent processes on the same patient.

Publication bias

When the likelihood of a study being published is affected by the findings of the study.

A distortion arising from systemic, institutional, interpersonal or individual forms of explicit (conscious) or implicit (unconscious) prejudice against individuals or groups based on social constructs of race or ethnicity that influences the planning, methods, results, interpretation, dissemination and application of health research.

Recall bias

Systematic error due to differences in accuracy or completeness of recall to memory of past events or experiences.

Referral filter bias

Referral of any group of unwell people from primary to secondary to tertiary care, causing an increase in the concentration of rare cases, more complex cases or people with worse outcomes.

Reporting biases

A systematic distortion that arises from the selective disclosure or withholding of information by parties involved in the design, conduct, analysis, or dissemination of a study or research findings

Review biases

Occurs in diagnostic test accuracy studies when the person interpreting the results of the index test has knowledge of the results of the reference standard (diagnostic review bias), or, the person interpreting the results of the reference standard has knowledge of the results of the index test (index review bias). Clinical review bias occurs when relevant clinical and patient information is available to the person interpreting the test or reference result. These are all forms of observer bias.

Catalogue of Bias

Positive results bias

Prevalence-incidence (Neyman) bias

Previous opinion bias

Publication bias

Racial bias

Recall bias

Referral filter bias

Reporting biases

Review biases

Selection bias

Spectrum bias

Spin bias

Starting time bias

Substitution game bias

Unacceptability bias