Countries that switch from non-democracy to democracy achieve about a 20% increase in GDP per capita over the following 30 years.
Democracy may encourage growth through: economic reforms, increasing human capital (especially through primary schooling), increasing investment, and reducing social unrest.
The impact of democracy on growth does not seem to depend on the level of development.
There is an economically and statistically significant positive correlation between democracy and future GDP per capita.
Democracy Does Cause Growth
Gross Domestic Product (GDP)