Achieving Consensus on Guidance for Specifying the Target Difference in a RCT Sample Size Calculation - DELTA2 Project

• Activity Number: 328 - New Guidance on Specifying the Target Difference (Effect Size) for a Randomised Controlled Trial
• Type: Topic Contributed
• Date/Time: Tuesday, August 1, 2017 : 10:30 AM to 12:20 PM
• Sponsor: Biopharmaceutical Section
• Author(s): William Sones* and Jonathan Cook
• Companies: University of Oxford and University of Oxford
• Keywords: Randomised controlled trial ; Sample size ; Effect size ; Target difference ; RCT ; Guidance

Abstract

Central to the validity of a randomised controlled trial (RCT) is an a-priori sample size calculation which ensures the study has a reasonable chance to achieve its pre-specified objectives. As highlighted in an earlier talk in the session, the sample size calculation is sensitive to the target difference. A number of techniques have been established for estimation of effect size. However, limited guidance into their application is available.

The DELTA2 (Difference ELicitation in TriAls 2) study aims to address this deficit in guidance by: determining the level of guidance already available; achieving consensus upon level of guidance, and identifying future research needs.

The DELTA2 project, presented here, included a systematic literature review of recent methodological developments and existing funder guidance, as well as a Delphi study as part of the process of developing guidance and achieving consensus.

This talk will discuss the methods and findings of the systematic review and of the Delphi study.