Problems in Sampling and Defining the Unit of Analysis in the Study of Policy Change"

Here are two problems arguably faced by those hoping to generalize about the determinants of policy change in Congress and other legislatures: First, what is the unit of analysis? Researchers often write of long-term changes in support for a "policy," but what Congress actually considers are bills, and bills die at the end of each two-year congress. Second, if we think of Congress considering a population of policy proposals, how does the researcher draw a sample to study? These questions have not been seriously addressed by social scientists. Possible answers will be suggested, with comments and other proposals welcomed.