How much did Proposition 99, the 1989 California tobacco program, reduce cigarette sales? This beginner Python tutorial teaches the synthetic control method, which builds a look-alike California from other states, finds about 19 fewer packs sold per person each year, and then tries hard to break that result. It comes with an interactive app that runs in your web browser.
What does it really mean to control for another factor in a regression? This Python tutorial uses a simulated fast food coupon campaign to show that any such result can be rebuilt by first removing what the other factors explain and then plotting what is left in a simple two-variable chart. It comes with an interactive app that runs in your web browser.
Did a policy really work if it also affected the comparison regions? scspill, a Python package, estimates both the true effect and the spillover to them.
Can we still find the true effect of a job training program on earnings if we compare trainees with ordinary survey respondents instead of a randomized control group? This Python tutorial shows that adding background characteristics fixes the estimate only when they adjust the expected earnings trend of the comparison group. It comes with an interactive app that runs in your web browser.
Do industrial parks bring more economic activity to nearby towns, and who benefits? This Python tutorial compares places that got a park with places that did not, before and after it opened, using simulated data modeled on Ethiopia, and also looks at household welfare and outcomes for women. It comes with an interactive app that runs in your web browser.
How did the 2004 tsunami affect the economy of Aceh, Indonesia, over the long run? This beginner-friendly Python tutorial uses simulated data, nighttime lights, and several causal methods to compare damaged and undamaged areas before and after the disaster.
Do gender quotas raise the share of women in national parliaments? In Stata, we compare 9 countries that adopted quotas in different years with look-alike groups built from 110 countries without quotas, and find an average gain of about 8 percentage points that varies a lot across countries. The tutorial includes an interactive app that runs in your web browser.
Did the 1988 tobacco tax in California reduce smoking? In Stata, we compare three ways of building a comparison for California from other states, including a newer method that blends their strengths, and all three agree that cigarette sales fell, though by different amounts. It comes with an interactive app that runs in your web browser.
Python companion to the R and Stata Double LASSO tutorials — same data, same five estimators, plus a hands-on introduction to the DoubleML library (DoubleMLPLR, DoubleMLIRM, and learner-robustness across LASSO, RandomForest, XGBoost).
Stata companion to the R Double LASSO tutorial — same data, same five estimators, replicating the Belloni-Chernozhukov-Hansen 284-control extension of Donohue and Levitt's abortion-and-crime panel with pdslasso, rlasso, and cvlasso.