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Estimation of the two-group pilot sample size with a cautionary note on Browne’s formula

Obodo, Scholastica; Toher, Deirdre; White, Paul


Scholastica Obodo

Paul White
Professor in Applied Statistics


Using data obtained from a pilot study, Browne (1995) proposed a procedure for estimating the sample size needed for a definitive two-arm randomised controlled trial when the minimal important difference is specified. Simulations confirm these findings. The results attributable to Browne are extended to consider the degree of error attached to sample size estimation using this procedure. A consideration of the error provides a simple mechanism to estimate the sample size needed for a pilot study so as to control the degree of error in the follow-on substantive trial.

Journal Article Type Article
Acceptance Date Sep 4, 2021
Publication Date Sep 30, 2021
Deposit Date Oct 20, 2022
Journal Journal of Applied Quantitative Methods
Electronic ISSN 1842-4562
Peer Reviewed Peer Reviewed
Volume 16
Issue 3
Keywords sample size, estimation, pilot study
Public URL
Publisher URL,issue-3/2_SDP.PHP