In this chapter, because many phenomena that are of interest to social scientists are not amenable to the straightforward application of experimental designs (which we focused on in Chapter 5), we present a number of designs that are more common in the social sciences. First, we look at the relation between the types of variables we study and the research designs we employ. We then discuss cross-sectional designs, quasi-experimental designs, and combined designs. We also discuss preexperimental designs, and we end by comparing the strengths and weaknesses of the various designs.