How much does war lower the living standards of a country? Using data on 160 countries from 1955 to 2015 in Stata, we follow each country over time to separate the damage of war from lasting national differences, and find that about half of the long-run cost works through weaker institutions. The tutorial includes an interactive app that runs in your web browser.
Does an economic downturn make civil conflict more likely? Using yearly data on more than 5,000 African regions in Stata, we treat rainfall shocks as a natural experiment for local economic activity, measured by night lights seen from space, and find that economic decline raises the risk of conflict. It comes with an interactive app that runs in your web browser.
Did the 1988 tobacco tax and anti-smoking campaign in California cut cigarette sales? In Stata, we use the synthetic control method, which builds a look-alike California from a mix of other states, and find that sales fell by about 19 packs per person per year. It comes with an interactive app that runs in your web browser.
Did an after-school tutoring program raise the grades of low-income high school students? Using simulated data on 35 schools in Stata, we compare how grades changed in schools with and without the program, and we check whether both groups were on similar paths before it started. It comes with an interactive app that runs in your web browser.
Does extra tutoring raise final exam scores? In Stata, we compare students who scored just below and just above the cutoff of 70 on an entrance exam that decided who got tutoring, and find gains of about 9 to 11 points. It comes with an interactive app that runs in your web browser.
Do all countries respond the same way to democracy or inflation? In Stata, we use a method that sorts countries into hidden groups that behave alike, and find that the average link between democracy and economic growth hides a strong positive effect in 57 countries and a negative one in 41. It comes with an interactive app that runs in your web browser.
Do carbon emissions first fall, then rise and then fall again as countries get richer? With 12 possible control variables there are thousands of possible models, so we use two data-driven methods that weigh or select the controls and test them on simulated data where we know the right answer. This Stata tutorial comes with an interactive app that runs in your web browser.
How does credit risk spread across banks? Using quarterly data on 350 American banks from 2006 to 2014 in Stata, we model bad loans that spill over between similar banks, persist over time and respond to shared economic shocks, and show that ignoring those shocks gives misleading answers. It comes with an interactive app that runs in your web browser.
What does it really mean to control for a variable in a regression? In Stata, we turn that idea into a picture: we strip out the influence of other factors and plot what is left, using examples on store sales, airline flights and worker wages. It comes with an interactive app that runs in your web browser.
Did expanding Medicaid in some American states raise health insurance coverage among low-income adults, and how much can we trust that answer? In Stata, we measure how far the states could drift apart before the estimated gain would disappear, turning a yes-or-no check into a clear measure of robustness. It comes with an interactive app that runs in your web browser.