Policy analysis is concerned with “who gets what” in politics and, more important, “why” and “what difference it makes.” We are concerned not only with what policies governments pursue, but why governments pursue the policies they do, and what the consequences of these policies are. Political Science, like other scientific disciplines, has developed a number of concepts and models to help describe and explain political life. These models are not really competitive in the sense that any one could be judged as the “best.” Each focuses on separate elements of politics, and each helps us understand different things about political life