Practical considerations for estimating clinical trial accrual periods: Application to a multi-center effectiveness study

Rickey E. Carter, Susan C. Sonne, Kathleen T. Brady

Research output: Contribution to journalArticle

28 Scopus citations


Background: Adequate participant recruitment is vital to the conduct of a clinical trial. Projected recruitment rates are often over-estimated, and the time to recruit the target population (accrual period) is often under-estimated. Methods: This report illustrates three approaches to estimating the accrual period and applies the methods to a multi-center, randomized, placebo controlled trial undergoing development. Results: Incorporating known sources of accrual variation can yield a more justified estimate of the accrual period. Simulation studies can be incorporated into a clinical trial's planning phase to provide estimates for key accrual summaries including the mean and standard deviation of the accrual period. Conclusion: The accrual period of a clinical trial should be carefully considered, and the allocation of sufficient time for participant recruitment is a fundamental aspect of planning a clinical trial.

Original languageEnglish (US)
Article number11
JournalBMC Medical Research Methodology
StatePublished - Mar 30 2005
Externally publishedYes


ASJC Scopus subject areas

  • Medicine(all)
  • Health Informatics

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