Since 1990, the American states have adopted a variety of reforms to regulate lobbying in an attempt to address a host of ethical issues. Such regulation can have important impacts on a variety of aspects of the legislative process because it typically impacts the relationships between legislators and lobbyists. How does such lobbying regulation vary across the states and over time? I have developed a measure of state lobbying regulation from 1990-2003. This measure validly captures the laws that limit relationships between lobbyists and legislators and, as such, can be used to help assess a variety of hypotheses about the legislative process.States have long sought to govern the relationship between legislators and lobbyists through ethics laws, lobbyist registration, and reporting requirements (Rosenthal 2001). Lobbying regulations are designed to curtail outright bribery and vote-buying but also to reduce the appearance of impropriety that reduces public trust in government. These regulations vary across states and time and may influence a variety of aspects of the legislative process. For example, South Carolina and Kentucky used to have lenient lobbying regulations but, following scandals over the past 10 years, these states now have extensive limitations on the relationship between lobbyists and legislators (Goodman, Holp, and Ludwig 1996;Ensign 1997).Scholars' ability to assess the impact of these laws has been hindered by the lack of a measure of lobbying regulation that is comparable across states and over time. Opheim (1991) assessed the variability of state lobbying regulation in the late 1980s with an index based on the definition of the term "lobbyist," the extent of disclosure required, and the oversight and enforcement of regulations. Other researchers have since expanded our understanding of lobbying regulation, both the factors affecting it and how these influence lobbying communities, using ad hoc measures (Brinig, Holat SIMON FRASER LIBRARY on June 1, 2015 spa.sagepub.com Downloaded from