Capture varies in both degree and kind, across regulations and agencies. This simple statement is as important as it is obvious, ultimately setting the stage for a new focus on the prevention of regulatory capture.

In tackling this variation head on, the study of capture is turning a corner. An early focus on models of regulatory decision making is increasingly giving way to fine-grained empirical work on special interest influence in the regulatory process. To be sure, weakness on the evidentiary front has long been an open secret in the field. Already in 1974 Richard Posner observed that “empirical research [on capture] has not been systematic.” As late as 2006, Ernesto Dal Bó declared in a review essay that “empirical evidence on the causes and consequences of regulatory capture is scarce.” Although Dal Bó's observation is still broadly correct today, it is becoming ever less so. A more detailed picture of the phenomenon is beginning to emerge, and many students of capture – including the authors of this volume – are rethinking their approach, asking not just what causes capture and what problems it creates, but what accounts for its relative strength or weakness in real-world situations.