The purpose of this course is to discuss the nature of research designs in political science. We will discuss general issues concerning the philosophy of science and social science. We will spend most of our time on practical concerns with research design issues that tend to bedevil empirical projects. And while we do not have time to cover all possible problems in that area, we will spend a lot of time on what is now one of the key debates occupying many social scientists – the question of causal identification which often arises from the non-random assignment of treatment conditions.