DSM practitioners and utility planners will not be making the appropriate investment decisions unless estimates of non-incented program effects are an integral component of DSM planning. The industry accepted term, free drivers, has been superseded by a new term, spillover. While the new term is more descriptive of what is being measured, this new terminology is still not descriptive enough for the DSM industry. Four forms of non-incented program effects, including spillover are defined along with their relationship to market transformation. Tighter bounds on the definition of spillover are proposed, along with a broader view of program participation. The definitions are clarified through a new version of B.C. Hydro’s technology tree, and appropriate measurement methodologies are outlined.