The pressure in many fields (notably medicine, health research, and education) for evidence-based results has increased the importance of the design and analysis of social investigations. This course will address three broad issues: the design and analysis of social experiments and quasi-experiments; the design and analysis of sample surveys; and how the interrelationships between the two approaches can inform generalization from experiments. There are two parallel streams in the course. First, the course will tackle the issues of generalization from three different perspectives: (i) the classic statistical design of experiments; (ii) the design of experiments and quasi-experiments in the social sciences; (iii) the design and analysis of sample surveys. Second, using a set of readings on research design in a variety of settings, we will consider how evidence from research is gathered and used. Randomized clinical trials in medicine, tests of interventions in education and manpower planning, and the use of scientific evidence in policy formulation will be among the examples.