Does Receiving an Earnings Supplement affect Union Formation?: Estimating Effects for Program Participants using Propensity Score Matching

Kristen Harknett, University of Pennsylvania

Abstract

This paper demonstrates a novel application of propensity score matching techniques: to estimate nonexperimental impacts on program participants within the context of an experimental research design. I examine the relationship between program participation, defined as qualifying for an earnings supplement by working full time, and marital union formation among low-income mothers in two Canadian provinces. I find that receipt of an earnings supplement substantially increased union formation in one province but not the other. A subgroup analysis based on propensities of program participation revealed that the positive effect on unions was concentrated among relatively disadvantaged participants. The techniques demonstrated in the paper are broadly applicable to studies in which take-up is less than 100 percent among those randomly-assigned to a program group.