to claim geographic or country specialization as the differentiating category. The division between comparative politics and international relations is artificial, as processes within nations shape international processes, and international processes shape processes within states. Some scholars have called for an integration of the fields. Comparative politics does not have similar "isms" as international relations scholarship. Methodology While the name of the subfield suggests one methodological approach (the comparative method), political scientists in comparative politics use the same diversity of social scientific methods as scientists elsewhere in the field, including experiments, comparative historical analysis, case studies, survey methodology, and ethnography. Researchers choose a methodological approach in comparative politics driven by two concerns: ontological orientation and the type of question or phenomenon of interest. (Mill's) comparative method Most Similar Systems Design/Mill's Method of Difference: This method consists in comparing very similar cases which only differ in the dependent variable, on the assumption that this would make it easier to find those independent variables which explain the presence/absence of the dependent variable. Most Different Systems Design/Mill's Method of Similarity: This method consists in comparing very different cases, all of which however have in common the same dependent variable, so that any other circumstance which is present in all the cases can be regarded as the independent variable. Subnational comparative analysis Since the turn of the century, many students of comparative politics have compared units within a country. Relatedly, there has been a growing discussion of what Richard O. Snyder calls the "subnational comparative method." See also Comparative historical research Comparative Political Studies Comparative law Critical juncture theory Historical institutionalism Historical sociology International relations Modernization theory Political science Political sociology Institutional economics References Further reading Alford, Robert R., and Roger Friedland. 1985. Powers of Theory. Capitalism, the State, and Democracy. New York: Cambridge University Press. Almond, Gabriel A. 1968. "Politics, Comparative," pp. 331–36, in David L. Sills (ed.), International Encyclopaedia of the Social Sciences Vol. 12. New York: Macmillan. Baldez, Lisa. 2010. "The Gender Lacuna in Comparative Politics". Perspectives on Politics 8(1): 199–205. Boix, Carles, and Susan C. Stokes (eds.). 2007. The Oxford Handbook of Comparative Politics. Oxford, UK: Oxford University Press. Campus, Donatella, and Gianfranco Pasquino (eds.). 2009. Masters of Political Science, Vol. 1. Colchester: ECPR Press. Campus, Donatella, Gianfranco Pasquino, and Martin Bull (eds.). 2011. Masters of Political Science, Vol. 2. Colchester: ECPR Press. Chilcote, Ronald H., 1994. Theories of Comparative Politics: