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The effects of the Americans with Disabilities Act: A longitudinal model analysis (Moon et al. 2003)

Citation

Moon, S., Chung, K, & Yang, D. (2003). The effects of the Americans with Disabilities Act: A longitudinal model analysis. Clinical Research and Regulatory Affairs, 20(4), 433-445.

Highlights

    • The study’s objective was to examine the impact of the Americans with Disabilities Act (ADA), both the original 1992 legislation and its 1994 extension, on working hours and employment among men with disabilities. 
    • The authors applied a multiple regression model to panel data from the 1989–1995 Survey of Income and Program Participation (SIPP).
    • The study found that working hours and employment decreased on average among all men with disabilities, regardless of their labor force participation, relative to men without disabilities after the ADA was first implemented in 1992. In contrast, relative working hours and employment increased for labor force participants who self-reported a disability after the law’s 1994 extension went into effect.
    • The quality of causal evidence presented in this report is low because the authors did not control for possible disparities in pre-intervention trends in working hours and employment among men with and without disabilities. This means we are not confident that the estimated effects are attributable to the ADA; other factors are likely to have contributed.

Intervention Examined

The Americans with Disabilities Act of 1990

Features of the Intervention

The ADA prohibits discrimination against persons with disabilities. Enacted in July 1990 and first implemented in January 1992, the law bars employers from discriminating against persons 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 may 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 analyzed a sample of male respondents ages 25 to 59 from four panels of the SIPP, who were surveyed from October 1989 to December 1995. They estimated multiple regression models using sample weights to compare pre- and post-ADA working hours and employment outcomes among men with disabilities to similar outcomes among men without disabilities, distinguishing between the effects of the 1992 and 1994 versions of the law. The models controlled for age, education, race, marital status, region, metropolitan status, and number of children. Individual-level fixed effects were included to account for unobserved characteristics of the men in the sample. To control for selection into the workforce, the authors repeated the analyses on a subsample of men who described themselves as labor force participants.

Findings

    • The study found that working hours decreased on average among all men with disabilities, regardless of their labor force participation, relative to men without disabilities after the ADA was first implemented in 1992.
    • In contrast, after the law’s 1994 extension went into effect, relative working hours increased for labor force participants who self-reported a disability
    • After the ADA first went into effect, the probability of employment significantly decreased for men with disabilities relative to men without disabilities, regardless of labor force participation. 
    • The relative probability of employment among labor force participants who self-reported a disability increased significantly following the ADA’s 1994 expansion.

Considerations for Interpreting the Findings

The authors do not show that trends in pre-ADA working hours and employment rates were similar among men with and without disabilities, either generally or among labor force participants. Therefore, the estimated impacts on working hours and employment might reflect preexisting trends and not the effect of the legislation.

Causal Evidence Rating

The quality of causal evidence presented in this report is low because the authors did not control for possible disparities in pre-intervention trends in working hours and employment among men with and without disabilities. This means we are not confident that the estimated effects are attributable to ADA; other factors are likely to have contributed.

Reviewed by CLEAR

October 2015

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