His current interests are in comparative political economy; the interaction of voters, political parties, budget and other political institutions, financial markets, and fiscal policies in industrial democracies. His recent research analyzes institutional transparency, accountability and corruption, and fiscal policy outcomes in OECD countries and US states. He is author, co-author, or editor of The Politics of Economic Decline (Cambridge University Press, 1979, reissued 2009), Political Economics (University of California Press, 1983), Cabinet Studies (Macmillan, 1975), Advances in Quantitative Methods (Elsevier, 1980), Perspectives on Positive Political Economy (Cambridge University Press, 1990), Competition and Cooperation (Russell Sage, 1999) and Positive Changes in Political Science (Michigan, 2007).