The work of disabled workers was rated as being of a higher quality than their able-bodies colleagues in the report, which also said that less than a quarter of employers have recruited from "disadvantaged" groups.
A third of respondents said they "actively excluded" such groups — which the institute defines as including the long-term unemployed, older workers and those without qualifications — although this is an improvement on the 62% who said they did when asked in 2005.
Respondents also backed schemes to make such groups more employable, with the most popular scheme being a 6-month, minimum wage internship co-funded by the government.
Gerwyn Davies, public policy adviser at the institute, said: "Employer reluctance to recruit from groups who have faced barriers to employment shows that the Government still faces a huge challenge in getting more economically inactive benefit claimants – especially those with a criminal record – off welfare and into work."