Public servants take an average of 11.5 days of paid sick days every year, Canada’s budget watchdog has revealed in a new report – not the 18 days of leave cited by Treasury Board President Tony Clement.

Clement has decried the high absenteeism rate among federal workers, arguing that something needed to be done about the average of 18.2 days of paid leave that public service employees were taking every year. He said that figure was 2.5 times the average seven days of sick days taken in the private sector, which he said stood at 6.7 days.

Clement said it was “simply unsustainable” for an employer to run a “modern, high-performing and effective work force" with that kind of absenteeism.

But in the report unveiled Thursday, the Parliamentary Budget Office says its investigation found that public administration workers took an average of 11.52 days of paid sick leave in 2011-2012.

It said the 18.26 days estimate cited by Clement included time missed due to workplace injuries and unpaid sick leave.

Public servants currently get 15 sick days per year, which they can carry over from one year to the next. If they use up their banked sick days, they can then take unpaid sick leave for up to 13 weeks, at which point they could qualify for long-term disability insurance.

Parliamentary Budget Officer Jean-Denis Frechette said on CTV’s Power Play Thursday that a Statistics Canada report found little difference when comparing public-sector sick leave to similar demographics within the private sector.

“You have more unions, you have more women as well, and you have an older population (in the public sector),” Frechette said. “For those three factors, (Statistics Canada) found that the difference is only 1.1 days of sick leave.”

The Parliamentary Budget Office looked into the 18.2 days estimate cited by Clement at the request of NDP MP Paul Dewar, who charged that Clement’s figures were overinflated.

Thursday’s report comes as the government and 17 unions gear up for another round of collective bargaining. The government has vowed to reform the public sick leave system, by scrapping existing sick leave benefits and replacing them with a short-term disability plan.

Several unions have vowed to fight the Treasury board over the planned changes.

Also included in the budget watchdog’s report was an estimate that the salary paid to federal public service employees for sick days was around $871 million in 2011-2012.

It noted that was about 68 per cent higher than the estimate for 2001-2002, after accounting for inflation.

But the report also noted there’s also been growth in the size of the federal public service and increases in wages over the last decade, as well as changes to the number of paid sick days available.

The report also found there was “significant variance” in the use of sick leave among different federal departments. The PBO said it would undertake a second study to better understand these differences and their costs.