We provide new measures of ethnic, linguistic and religious fractionalization for about 190 countries. These measures are more comprehensive than those previously used in the economics literature and we compare our new variables with those previously used. We also revisit the question of the effects of ethnic, linguistic and religious fractionalization on quality of institutions and growth. We partly confirm and partly modify previous results. The patterns of cross-correlations between potential explanatory variables and their different degree of endogeneity makes it hard to make unqualified statements about competing explanations for economic growth and the quality of government.