Political Science is the field concerning the theory and practice of politics and the description and analysis of political systems and political behaviour. Topics in Political Science include political theory and philosophy, political concepts, political systems, ideology, game theory, electoral-voting systems, psephology (voting theory and electoral statistical analysis), geopolitics and political geography, political economy, policy studies and public policy analysis, comparative politics/cross-national political analysis, national political systems (eg, centralisation, regionalism, federalism, core-periphery studies, nation-state analysis etc), international political systems (eg, supranationalism, intergovernmentalism, military alliances, hegemony studies), globalisation studies, political development, postcolonialism studies, institutional theory, international relations, foreign policy analysis, peace studies, conflict analysis, strategic studies, diplomacy studies, international law and politics, public administration and local government studies, political party and coalition analysis, political psychology, political sociology and socialisation studies, micropolitical/behavioural analysis, political history, interest group/pressure group/lobby politics (especially environmental politics/political ecology), bureaucractic studies, administrative and judicial behaviour, legislative processes and public law. Political Science also studies power in international relations and the theory of great powers and also superpowers. Political Science is methodologically diverse. Approaches to the discipline include classical political philosophy, interpretivism, structuralism, and behavioralism, rationalism, realism, pluralism, and institutionalism. Political science, as one of the social sciences, uses methods and techniques that relate to the kinds of inquiries sought: primary sources such as historical documents and official records, secondary sources such as scholarly journal articles, survey research, statistical analysis, case studies, and formal model building.