What we talk about when we talk about statistical power

Music City Center 

Study proposals typically include a sample size justification in order to communicate that the study has been designed rigorously; but all too often, a biostatistician has been engaged at the final stages of proposal development with the sole purpose of providing this justification. We argue that a power calculation is the wrong deliverable for a biostatistician. Instead, biostatisticians should be integrated as full collaborators, working closely with the study team throughout the entire design process. We argue in two steps. First, practically speaking, there is no such thing as a "quick and easy" power calculation: these calculations depend on a comprehensive understanding of the intricacies and limitations of the study, which often requires extensive discussions with the study team to fully communicate. Second, including a study design and statistics expert as an equal partner produces more informative and reliable studies overall. We draw on our experiences as directors of collaborative statistical cores and offer specific recommendations for biostatisticians, clinical investigators, funding agencies, and research institutions to support this culture shift.

Statistical power

Study design

Collaborative statistics

Statistical consulting

Informative trials 

Section on Statistical Consulting