Mandatory Social Security coverage would cost public schools in Illinois $3.4 billion over 10 years, according to a study released in April by the Teachers' Retirement System of Illinois and the Illinois State Universities Retirement System.

Despite the extra costs, retirees, according to the study, would "almost certainly" receive lower benefits than they do now because pension contributions would probably be reduced to partially offset the new Social Security costs, and "the dollars contributed by the employer and by the member to Social Security 'buy' lower benefits than the dollars contributed to the retirement systems."

Students would also suffer as a result of mandatory coverage, the study concluded.

"The conversion of existing retirement systems to include Social Security would inevitably reduce funds available for education programs and services," the report stated. "For example, there would likely be teacher layoffs, reduced textbook spending, less computer access, and fewer new and innovative programs to prepare students adequately for the workplace. The impact on higher education would be similar, but it may also include tuition and fee increases and enrollment limitations. The reductions and cutbacks would be different at every institution, but it is clear that teachers, administrators, and school board members would be forced to make tough choices that would reduce educational opportunities."

The Segal Company found in 2005 that mandatory coverage would cost Illinois $4.2 billion over five years.