Research Methods

Designing More Efficient Studies with Group Sequential Designs

Creating studies that are powered to detect the smallest effect of interest... without collecting more data than you need to detect bigger effects

Correctly Dealing with Outliers (Part One)

A two-part blog post on outlier exclusion procedures, and their impact on false-positive rates.

Outlier Exclusion Procedures Must be Blind to the Researcher's Hypothesis

How should researchers exclude outliers: Across the data, or within conditions? In this paper, I show that when outlier exclusions are performed in a way that is not 'blind' to the researchers' hypothesis (e.g., within conditions), they increase Type I error to unacceptable levels.