An undergraduate honors thesis using Massachusetts (MA) health reform (2006) as a difference-in-differences (DiD) natural experiment to estimate the causal effect of affordable health insurance access on the Supplemental Security Income (SSI) acceptance rate. Yates finds that MA reform raised the initial SSI acceptance rate by approximately 6 percentage points (pp) (13.5% relative to baseline) and the total acceptance rate by ~7.3 pp (17.6%), with timing evidence favoring the applicant pool channel (marginal able applicants exiting the program because SSI's Medicaid value falls) over the application quality channel (better medical documentation from more frequent doctor visits).
"I find that Massachusetts health reform increased the initial SSI acceptance rate by around 13 to 19 percent. I then find suggestive results that a change in applicants is driving the effect."
"The SSI program is unique in its disability determination process. Even though the Social Security Administration created an extensive screening mechanism to accurately and uniformly evaluate each applicant's disability status, information asymmetry still persists in the program."
A credibly identified undergraduate thesis — the MA health reform DiD design is well established in the literature and Yates applies it to the acceptance rate, a novel and policy-relevant outcome variable (prior studies focused on application counts or program participation). Key limitations: only six New England states as the control group (small donor pool); one of the pre-period placebo checks (column 2, Table 4.7) shows a marginally significant coefficient, a partial challenge to parallel trends; the "good candidate" ACS definition imperfectly proxies for truly disabled individuals; undergraduate thesis lacks the peer-review robustness of published work. The theoretical Akerlof tagging framework is appropriate and the two-channel logic is clean. The finding that applicant pool composition (not application quality) drives the acceptance rate increase is credible and has immediate policy relevance: ACA Medicaid expansion predictably improved SSI applicant pool quality in expansion states. The paper is one of the few studies treating the SSI acceptance rate itself — rather than application volume or enrollment — as the dependent variable.