Policy evaluation research - Measuring the independent variables

The purpose of this article is to evaluate the accuracy of three methods used to obtain policy data: (a) government agency surveys, (b) secondary sources; and (c) historical legal research. Changes In laws were identified for all 48 contiguous states for the period 1968 to 1994. Legal research is most accurate for well-established laws that have consistent legal descriptions across nearly all states. Laws that are recently enacted, adopted by only a few states, and treated in a legally inconsistent manner across states require a multistage data collection method to identify accurate policy change information.