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

Abstract

Voluntary measures have traditionally been evaluated using a similar framework regardless of their structure. The framework assumes that the measure provides partners with a treatment (information, research support, etc) that will not be transferred to non-partners. In this framework, a voluntary measure 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 measures take many different forms; some which are expected to have transfers (spillovers) to non-partners. The Coal Combustion Products Partnership (C2P2) is a U.S. voluntary program with a structure that is likely to provide treatment spillovers to non-partners. This paper evaluates C2P2 and tests whether treatment spillovers are affecting non-partners’ behavior. Results are consistent with a program that would traditionally been considered unsuccessful, however when treatment spillovers are considered, is consistent with a successful program.