Speaker: Prof Steven Julious, University of Sheffield

Title: “Sample size considerations for the design clinical trials – quantifying the target difference and the target no-difference”

Abstract: One of the most of the important steps in any clinical trial design is the calculation of the sample size calculation.  From this the study timelines and financial budgets are calculated.  A major driver in the sample size calculation size calculation is the target difference (for a superiority trial) or the target no-difference (for a non-inferiority trial)

How these are quantified will impact on their estimation.  The most common approach is to review the treatment effects that have been observed previously.  The can be issues with this approach as what has been seen in the past does not carry forward to future trials.

For a superiority trial an inaccurately quantified target difference could mean the study does not have sufficient sample size and so inadequate power to show an effect.  For a non-inferiority trial the effect of an inaccurately quantified non-inferiority limit could be consider more of an issue as it could mean false conclusions of no effect are made.

In this talk will highlight the issues with quantifying target differences or non-inferiority limits and will make practical recommendations.