A Simple Way to Teach Regression

This paper introduces a simple free web app that can teach regression to anyone who can point and click. Originally designed to teach Justice Department attorneys enough about regression so that they could cross examine rival experts, the app ``inverts'' the usual pedagogy: instead of showing users how to run regressions on data, it asks them to click on a graph to ``create'' data to achieve a given outcome, like a statistically significant line. Successful completion of each task is rewarded with immediate feedback that reveals the principle behind the exercise. This paper describes short, intuitive exercises to teach: (i) hypothesis testing, statistical significance and confidence intervals, (ii) the difference between correlation and causality, and (iii) how to diagnose functional form mis-specification. These exercises can be completed in just a few minutes