Diff-in-Diff in Panel Data

Overview

This module covers regression approaches to difference-in-differences estimation (without staggered treatment timing). We review the basic two-by-two difference-in-differences regression specifications, and discuss extensions that allow for continuous variation in treatent intensity and the inclusion of period-specific and unit-specific fixed effects.

Readings

Does a ban on informal health providers save lives? Evidence from Malawi by Susan Godlonton and Edward Okeke.

Lecture Slides

A handout version of the lecture slides is available here.

Video Lectures from 2021

Lecture 5.1: 2X2 Difference-in-Differences Specifications (19:34)

Lecture 5.2: Diff-in-Diff with Continuous Treatment Variation (28:06)

Lecture 5.3: Diff-in-Diff with Time Period Fixed Effects (19:14)

Empirical Exercise

The stata version of the empirical exercise is available here.

The R version of the empirical exercise is available here.

The python version of the empirical exercise is available here.

The python version is also available here as a colab.

Acknowledgments

Special thanks to Patrick Blanchenay, Garret Christensen, Liz Cascio, Jess Goldberg, Guy Grossman, Kirabo Jackson, Michael Kevane, Scott Imberman, Manisha Shah, and Mike Urbancic for their diff-in-diff suggestions.