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Compound Evidence InstituteEvidence synthesis · established 2023Graded assessments of compounds, trials, methods and supply
Document set current to 30 July 2026
Defined term · Trial design and conduct

Attrition

Loss of participants from a trial before its primary analysis timepoint. Differential attrition between arms threatens the comparability that randomisation established.

Document identifier
CEI-GT-050
Series
Defined term
Version
1.0
Published
30 Jul 2026
Last reviewed
30 Jul 2026
Certainty
Not rated

§1Attrition

§1.1Also known as

Loss to follow-up

§1.2Category

Trial design and conduct — Terms describing how a clinical study is constructed and run.

§1.3Related terms

  • Intention to treat — Analysis of participants in the group to which they were randomised, regardless of the treatment they received. Preserves the comparison randomisation created and…
  • Risk of bias — The extent to which features of a study’s design or conduct could produce an effect estimate that systematically departs from the truth. Assessed at the level of the…
Compound Evidence Institute · CEI-GT-050 · https://compoundevidence.com/glossary/attrition/ · retrieved 30 July 2026
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