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