Evaluating Voluntary Programs with Spillovers: The Case of Coal Combustion Products Partnership

The framework for voluntary program evaluation assumes that voluntary programs provide partners with information that will not be transferred to non-partners. In this framework, a voluntary program is said to be worthwhile if there are significant differences between the behavior of partners and non-partners, correcting for the potential endogeneity of becoming a partner. However, voluntary programs take many different forms; some which are expected to have information transfers (program spillovers) to non-partners. The Coal Combustion Products Partnership (C2P2) is a program to increase the re-use of coal combustion products (CCP) using a structure that is likely to provide spillovers to non-partners. This paper evaluates C2P2 and tests whether program spillovers are affecting non-partners’ behavior. Results suggest that the traditional interpretation would find this program unsuccessful, however when spillovers are considered, evidence points to a successful program.