title: Sample size calculations for within-patient comparisons with a binary or survival endpoint.
abstract: Formulae are derived for the required number of failures needed in a randomized clinical trial with a binary or survival endpoint in which treatments are compared using multiple units within each patient. Calculation of the required total numbers of units and patients are illustrated by examples. These show that naive use of conventional calculations could underestimate the number of units and patients required, particularly if the number of units per patient is small.
authors.affiliation: National Centre in HIV Epidemiology and Clinical Research, University of New South Wales, Sydney, Australia.
authors.forename: M G
authors.initials: MG
authors.lastname: Law
mesh_terms: D006801:Humans; D016032:Randomized Controlled Trials as Topic / Q000379:methods*; D018401:Sample Size; D015996:Survival Rate; D016896:Treatment Outcome