The North Carolina Solar Center at NC State University, in collaboration with the National Renewable Energy Laboratory, examined 10 state financial-incentive programs in six states using a case-study approach in order to clarify the key factors-both internal and external to the program-that influence their effectiveness at stimulating deployment of renewable energy technologies. While existing information resources such as the National Database of State Incentives for Renewable Energy (DSIRE, www.dsireusa.org) have documented what incentive programs are available, the effectiveness of such programs is not well understood. Understanding the impact of current financial incentives on the deployment of renewables and the factors that influence their effectiveness is critical to a variety of stakeholders, particularly in states considering new incentives or interested in improving or discarding existing ones.