In recent decades, modernization theory has been challenged. Studies have found that richer countries are more likely to maintain democratic rule, but that the initial transition to democracy is unrelated to economic development, or that even the former relationship is spurious, disappearing once country fixed-effects are accounted for. Others counter that the relationship between development and democracy is restored if historical data stretching back to the nineteenth century is incorporated, if different estimators are used, or when conditioning the relationship on institutional or leadership changes taking place. Thus, the modernization debate, at present, rests upon a complex set of modeling choices.
Carl Henrik Knutsen, John Gerring, Svend-Erik Skaaning, Jan Teorell, Matthew Maguire, Michael Coppedge, and Staffan Lindberg. "Economic Development and Democracy: A Disaggregated Perspective" Annals of Comparative Democratization (2018): 7-11.