Acemoglu, D., & Angrist, J. (2001). Consequences of employment protection? The case of the Americans with Disabilities Act. Journal of Political Economy, 109(5), 915-957.
- The study’s objective was to examine the consequences of the Americans with Disabilities Act (ADA) on the employment and wages of people with disabilities.
- The main analysis estimated regression models of weeks worked and weekly earnings as a function of self-reported work disability status, allowing effects to differ each year and controlling for factors relating to demographics, region, and time. Data came from the 1988–1997 March Current Population Survey.
- The study found that a year after the ADA came into effect (1993), the employment of men and women ages 21 to 39 with disabilities declined and this change could not be explained by potential changes in how individuals reported disability status or by increases in Supplemental Security Income (SSI) or Old-Age, Survivors, and Disability Income (OASDI).
- The quality of causal evidence presented in this report is moderate because it was based on a well-implemented nonexperimental design. This means we are somewhat confident that the estimated effects are attributable to the ADA, but other factors might also have contributed.
The Americans with Disabilities Act of 1990
Features of the Intervention
The ADA prohibits discrimination against people with disabilities. Enacted in July 1990 and first implemented in January 1992, the law bars employers from discriminating against people with disabilities in all aspects of employment, including hiring, firing, wages, and training. The legislation also requires employers to provide reasonable accommodations to help employees with disabilities complete the functions of their jobs, provided the accommodations do not impose undue hardship on the employer. Reasonable accommodations include adjusting work schedules or equipment, providing qualified readers or interpreters, or modifying facilities to improve accessibility. When the ADA first went into effect in 1992, it applied to government employers and private employers with 25 or more employees; an addendum in 1994 extended coverage to private employers with 15 or more employees.
Features of the Study
The authors estimated regression models comparing weeks worked and weekly earnings of people with and without disabilities, separately by gender and 10-year age groups, before and after the passage of the ADA in July 1992. The models controlled for disability status, demographic characteristics, and region- and year-fixed effects, as well as separate pre-intervention trends in the outcome variable for people with and without disabilities. A set of interactions of disability status with year indicators identified the impact of the ADA on people with disabilities.
- The year after the ADA took effect (1993), the employment of men and women ages 21 to 39 with disabilities declined significantly. The change could not be explained by potential changes in how people reported disability status or increases in SSI or OASDI.
Considerations for Interpreting the Findings
The authors controlled for separate pre-intervention trends for people with and without disabilities to help ensure the comparability of the two groups and the validity of the results. The authors also conducted supplementary analyses that supported the main findings. These analyses accounted for receipt of SSI and OASDI benefits for people with disabilities, a factor that can affect employment while also being a consequence of employment status. The analyses also used matched Current Population Survey samples from adjoining years, focusing on people reporting the same disability status in both years, to show the findings were robust to potential bias due to any effect of the ADA on the reporting of disability status.
Causal Evidence Rating
The quality of causal evidence presented in this report is moderate because it was based on a well-implemented nonexperimental design. This means we are somewhat confident that the estimated effects are attributable to the ADA, but other factors might also have contributed.