Political science is a social science which deals with systems of governance, and the analysis of political activities, political thoughts, associated constitutions and political behavior.
Political science comprises numerous subfields, including comparative politics, political economy, international relations, political theory, public administration, public policy, and political methodology. Furthermore, political science is related to, and draws upon, the fields of economics, law, sociology, history, philosophy, geography, psychology/psychiatry, anthropology and neurosciences.
Comparative politics is the science of comparison and teaching of different types of constitutions, political actors, legislature and associated fields, all of them from an intrastate perspective. International relations deals with the interaction between nation-states as well as intergovernmental and transnational organizations. Political theory is more concerned with contributions of various classical and contemporary thinkers and philosophers.
Political science is methodologically diverse and appropriates many methods originating in psychology, social research and cognitive neuroscience. Approaches include positivism, interpretivism, rational choice theory, behavioralism, structuralism, post-structuralism, realism, institutionalism, and pluralism. 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the social sciences, uses methods and techniques that relate to the kinds of inquiries sought: primary sources such as historical documents and official records, secondary sources such as scholarly journal articles, survey research, statistical analysis, case studies, experimental research, and model building.