Well, it's October, and the World Series is under way. Good time to talk baseball I'd say. So here's a blast from my own past on the subject: Simpson's Paradox and Major Leagues Baseball's Hall of Fame.¹

We recently had the pleasure of attending a seminar by one of the world's experts on the presentation of quantitative data and information. At turns witty, sardonic, or professorial, "ET" (as he is affectionately known by his fans) was entertaining and informative in Presenting Data and Information: A One Day Course Taught by Edward Tufte.

One of the most important aspects of good research is proper study design; no type or amount of statistical analysis can make up for a poorly designed study. In longitudinal research one of the most important aspects of study design is making sure that the temporal sequence of events is understood and recorded correctly. Errors in this arena can lead to misclassification of exposure time and differential follow-up between comparison groups. It is therefore crucial to understand time at risk in studies and correctly and fairly apply rules of follow-up to study subjects.