Disclaimer. Don't rely on these old notes in lieu of reading the literature, but they can jog your memory. As a grad student long ago, my peers and I collaborated to write and exchange summaries of political science research. I posted them to a wiki-style website. "Wikisum" is now dead but archived here. I cannot vouch for these notes' accuracy, nor can I even say who wrote them. If you have more recent summaries to add to this collection, send them my way I guess. Sorry for the ads; they cover the costs of keeping this online.
Savage. 1978. Policy innovativeness as a trait of American states. Journal of Politics 40:212-224.
Walker's (1969) study assumed "innovativeness" was a trait that states had or not. Gray (1973) rightly criticized him for failing to recognize that innovativeness varies across issue and over time--states that are innovative on certain issues during certain periods aren't necessarily innovative on other issues during other periods.
INNOVATIVENESS VARIES OVER TIME
Savage asks whether innovativeness really is an enduring state characteristic. He studies 181 policies, doing his best to cover diverse issue areas. As shown in Table 1, innovativeness does not correlate well over time (correlations of 0.27 and 0.31), at least not anymore: innovativeness in the early 20th century did correlate well with innovativeness in the 19th century (r=0.62).
VARIATION OVER ISSUES?
Although he apparently had plenty of data, for some reason Savage does nothing to assess whether innovativeness varies over issues (as Gray claimed it does). I can't think why he didn't.
Research on similar subjects