Over the past few decades, governments around the world have established procedures to try to analyze the impacts of new regulatory proposals before they are adopted. By contrast, they have paid remarkably little attention to analyzing regulations after adoption. Admittedly, some countries have begun to undertake modest efforts to examine the impacts of regulation retrospectively. Under the Obama Administration, for example, agencies across the United States government have undertaken a formal “look back” review to identify and remove outdated regulations. But by and large these kinds of look-back efforts, however valuable they may be for tidying up the law books, fall far short of the kind of rigorous evaluation research needed to determine which regulations are causing positive outcomes and which ones are not.