Employers — especially at small companies — are far less likely to respond to job seekers with disabilities, according to findings from a field test looking at thousands of applications.

Using fake cover letters, researchers found that job applicants who mention a disability are 26 percent less likely to hear back from employers, according to findings reported in a working paper from the National Bureau of Economic Research.

For the study, researchers sent in applications in response to 6,016 advertised openings for accounting positions. All of the fictional applicants were appropriately qualified for the jobs, half of which were entry level while half were for more experienced professionals.

In one third of cases, the applicants disclosed a diagnosis of Asperger’s syndrome, another third said they had a spinal cord injury and the remainder revealed no disability.

Response rates did not differ based on disability type, the study found, but the size of the employer and the job sought did seem to make a difference.

Businesses with fewer than 15 employees were least likely to respond to job seekers with disabilities. These applicants garnered more interest when applying to government jobs, publicly-held companies and firms that contract with the federal government, according to the results, which have not been peer reviewed.

More experienced job candidates with disabilities appeared to have the most difficulty, researchers found, with such applicants 34 percent less likely than those without a disability to generate interest from employers.

“The overall pattern of findings is consistent with the idea that disability discrimination continues to impede employment prospects of people with disabilities, and more attention needs to be paid to employer behavior and the demand side of the labor market for people with disabilities,” wrote researchers from Rutgers University and Syracuse University.