There is a plethora of studies on interest groups in the European Union. While these studies have generated a wealth of insights, it is not actually clear what they have accomplished. This Living Review seeks to identify those areas of interest group studies in which our knowledge is fairly consolidated and in which major research gaps or major controversies can be noted. I argue that these res...

A simultaneous equations model is estimated to analyze the interaction between state Medicaid pharmaceutical drug reimbursement rates, drug recipients per capita, and expenditures per drug recipient. Interest groups are shown to have a strong positive impact on pharmacy reimbursement rates, which, in turn, have an impact on pharmacy participation rates and drug utilization and expenditure patte...