People with disabilities are not necessarily sick or in need of constant medical attention, but even if an individual with a disability had medical costs higher than others, they would likely have a minimal impact on a company's insurance premiums because of how insurance rates are often calculated. Health insurance rates work on the principle that any given group will have a mix of people who range from those who never go to a doctor to those who have ongoing health care needs. The vitality of a health plan depends on the premiums of all in the pool paying for the higher medical costs of the few people with greater needs.
As stated by the Disability Program Navigator website of Sutter County, California, "Many businesses express fear and concern that if they hire workers with disabilities the companies insurance costs will go up. A survey of human resource managers, conducted by Cornell University, has found that companies' health, life and disability insurance costs rarely rise because of hiring employees with disabilities. However, attitudinal stereotypes about people with disabilities are still pervasive in the workplace, causing them to be hired less and fired more than workers without disabilities."
For more information about hiring and retaining workers with disabilities, consult the Knowledge Base articles Why Should a Company Hire a Person with a Disability? and In What Ways Does the Americans With Disabilities Act Protect Job Applicants