statistics

Why replication matters: Insights from replicating 10 online privacy studies

Several times, I tried to get a replication project funded. Every time, reviews came back with a the same results: a worthwhile idea, but not feasible. Often the concern were the costs, other times the sample size we would need. Overall, between the lines, there seemed to be a vague doubt about whether replication is really “original” enough to even deserve a grant. Well, times have changed now, but for the longest time, replication was… Read More »Why replication matters: Insights from replicating 10 online privacy studies

How to visualize interaction effects

I recently gave a workshop on data visualization. One of the topics was visualizing interaction effects (or “moderation” analyses). I think it is a great topic because it exemplifies quite well that there is not one solution to all problems. In general, I would argue that trying to visualize interaction effects is great idea. Due to the conditional nature of the effects obtained from standard regression analyses that include an interaction term, it is often… Read More »How to visualize interaction effects

How to center in multilevel models

Have you ever thought about centering your variables before running an regression based analysis? From my personal experiences, chances are high are that you haven’t: Although a useful data transformation procedure for many statistical analyses, centering is seldom taught in fundamental statistic courses. Although the mathematical principles behind it may seem arbitrary, its implications are oftentimes quite strong. Although centering is already useful in standard statistical modeling (e.g., OLS regression), its usefulness is particularly evident… Read More »How to center in multilevel models