Growth regressions are one way to assess the effect of institutions on economic growth.
Another way is to consider human capital and political institutions in the sample of poor countries
circa 1960. To this end, we divide our 1960 sample of countries into those with low human capital
(total years of schooling per capita below the median value of 2.68), intermediate human capital
(schooling between 2.68 and 5.01 years per capita), and high human capital (schooling above the
75th percentile value of 5.01 years per capita). We independently divide this sample into four types
of political regimes using the 1960-2000 average Polity IV democracy score: autocracies (countries
with the average score under 2), stable democracies (countries with the average perfect score of
10), and two intermediate groups: imperfect autocracies (the average score between 2 and 7) and
imperfect democracies (the average score between 7 and 10). Autocracies include places like Saudi
Arabia, Vietnam, and Yemen. Stable democracies cover all the usual developed countries (except
that it includes Costa Rica but not France).