Sample Size Determination for Clinical Trials
Sample size estimation is as much an art as it is a science. Calculating sample size needed for a clinical trial that optimally ensures sufficient power, while not requiring excessive costs and recruitment time is both a matter of statistics as well as communication with the research team.
We work with your team to determine the investigatory questions being asked and the hypothesized answers. We then discuss concrete examples of how additional or fewer subjects may impact the study results and its interpretations.
Since budget is undoubtedly a limitation in sample size, we can assist by determining the value of the effect size, relative to scientific goals. If the effect size is too large, and the study is under-powered, then either that information can be used to argue for a larger budget, or the study design can be examined to see if there is a way to reduce the variance, such as through stratification or narrowing the scope of the study.
In short, determining the correct sample size involves communicating clearly with the research team to clarify their options and weigh the impact of their choices.