Source: Fernández, C., E. Ley, and M. F. J. Steel. 2001. Model uncertainty in cross-country growth regressions. Journal of Applied Econometrics 16: 563–576. https://doi.org/10.1002/jae.623.
This index was developed by Freedom House.
This is an index based on the degree of capitalism from  Hall and Jones (1996). Hall, R. E., and C. I. Jones. 1996. The productivity of nations. Working paper 5812, National Bureau  of Economic Research. Cambridge, MA.
Average annual growth in GDP per capita from 1960 to 1992,  from the Penn World Tables, Rev. 6.
This variable is identical to variable gdpgrowth.