This article reviews the literature featuring quantitative interest group research at
the national and subnational level in the United States. We direct scholars to existing
resources and techniques. Additionally, we make recommendations on methods
and discuss the limitations of prevailing measures. The appropriate measure
is driven by the research question and data availability. However, since money is a
central resource in politics, every attempt should be made to include organization
or sector financial resources when investigating the relative strength of groups in
policymaking.
