Academic

We find overall that the use of legislative history is driven by a combination of legal and ideological considerations. On the whole, the legal variables have a significantly larger impact on the likelihood of legislative history usage than the ideological variables, but the impact of the ideological variables cannot be dismissed. The complexity of a statute increases the likelihood of legislative history usage, whereas frequently amended statutes are less prone to receive such treatment. The age of the statute also matters, but its effect is neither linear nor monotonic: very new and very old statutes are less likely to elicit legislative history usage than statutes of intermediate age. The evidence also suggests that the use of legislative history by one justice prompts other justices to respond in kind with legislative history arguments of their own. With respect to the impact of ideological factors, liberal justices are generally more likely than conservative justices to cite legislative history. As a result, the rightward shift in the ideological composition of the Court has largely coincided with a decline in the overall use of legislative history since the mid-1980s.

We found no support, however, for the proposition that justices use legislative history instrumentally in order to reach their ideologically preferred outcomes: legislative history usage does not affect the likelihood that a justice will arrive at his or her preferred outcome. Moreover, contrary to what some scholars have suggested, we also found no evidence that Justice Scalia has persuaded other justices to refrain from citing legislative history in their own opinions.