The Polity project is one of the most widely used data resources for studying regime change and the effects of regime authority. The Polity5 Project, which studies Political Regime Characteristics and Transitions from 1800-2018, is an annual, cross-national, time-series dataset which codes democratic and autocratic ''patterns of authority'' and regime changes in all independent countries with a total population greater than 500,000 in 2018 (167 countries in 2018).