Many Americans living with a disability are reluctant to disclose that information if it can be avoided. It’s not that they are ashamed or embarrassed of living with a disability. Instead, they know from firsthand experience that disability discrimination is a very real threat. Statistics from 2013 show that just 34 percent of working-age Americans with disabilities are employed, compared to about 74 percent of people without disabilities.

Some of this disparity could be attributed to disabilities that make it difficult or impossible to work a job. But that still leaves a significant portion of capable job candidates who face discrimination because of a disability that would have no impact on their ability to work. The results of a recent study suggest that disclosing a disability during the hiring process could dramatically reduce one’s chances of finding work.

Researchers from two universities sent out thousands of fictitious résumés and cover letters for jobs in the accounting profession. The fictitious job seekers were substantially similar in all ways except one. In some of the cover letters, the fictitious candidates disclosed a disability. In others, they did not.

When a cover letter disclosed a disability, employers expressed interest in those candidates about 26 percent less often than for candidates with a cover letter that did not mention disability.

The cover letters experiment has been used successfully to research employment discrimination based on other characteristics as well, including race and gender. Previous research has shown that companies were less likely to be interested in job candidates with “black sounding” names, even if those candidates had stronger résumés than their presumptively white counterparts.

The Civil Rights Act and the Americans with Disabilities Act were both important pieces of legislation, but these laws have not done enough to end illegal workplace discrimination. Hopefully, studies like this one will compel employers to re-examine their own beliefs to determine if unconscious bias may be causing them to overlook qualified job candidates.