Research
Long-Run Determinants and Idiosyncratic Factors of Social Security Disability Insurance Rates
Despite general improvements in health, and legislation designed to facilitate labor force participation among Americans with disabilities, the percentage of working-age adults receiving Social Security Disability Insurance (SSDI) increased nearly 150% from 1986 to 2013. SSDI award is a function not only of health, but also an individual’s employment potential. In 2013, nearly one in twenty working-age adults was out of the labor force and receiving SSDI. Since 2013, however, the increasing trend reversed, and the number of SSDI recipients has been persistently falling. States and counties display the same general trend in disability rates, however, there exists a large degree of state and county level variation across the US. In 2013 state SSDI rates ranged from 2.75% to 8.6%, and county rates ranged from 0.64% to 21.28%. I find that the percentage of the population between the ages of 55 and 59 is what drives the long-run trend in the percent of working-age adults receiving SSDI, and I use this finding to forecast future national and state SSDI rates. Additionally, I show that non-health forces are important determinants of county-level SSDI rates by demonstrating that local exposure to negative employment shocks leads to increases in SSDI growth two to five years later.
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Policy Evaluation with Nonlinear Trended Outcomes: COVID-19 Vaccination Rates in the US
This paper discusses pitfalls in two-way fixed effects (TWFE) regressions when the outcome variables contain stochastic trend components. If a policy change shifts trend paths of outcome variables TWFE estimation can distort results and invalidate inference. A robust solution is proposed by allowing for dynamic club membership empirically using a relative convergence test procedure. The determinants of respective club memberships are assessed by panel ordered logit regressions. The approach allows for policy evolution and shifts in outcomes over time according to a convergence cluster framework with transitions over time and the possibility of eventual convergence to a single cluster as policy impacts mature. An application to new weekly US COVID-19 vaccination policy data reveals that Federal-level vaccine mandates produced a merger of State vaccination rates into a single convergence cluster by mid-September 2021.