The debate on pay rates in the public and private has been undermined by the "deliberate misrepresentation" of earnings data by several leading commentators including the Economic and Social Research Institute (ESRI), the State's largest trade union has claimed.
Siptu today published its own research on wage differentials between the sectors which it said dispelled the "myth and lies" surrounding public servants' pay, and showed private sector managers benefited most from the boom.
According to the research - Separating Fact from Fiction on Earnings: The Use and Abuse of Statistics- private sector managers have seen their pay jump by approximately 40 per cent since 1998, while average public sector salaries, when the pension levy is included, has risen only 17.6 per cent.
In the more recent period since December 2005, the report suggested public sector workers had received pay increases of 12 per cent, while managers in the private sector enjoyed increases of 13.5 per cent, with manual workers in the private sector receiving increases of only 5.4 per cent.
When inflation and the pension levy, imposed on public servants in March, are taken into account, the only group whose wages exceeded inflation was private sector managers, the study said.
An ESRI report, published in September, found that public sector workers were earning up to 26 per cent more than their counterparts in the private sector in 2006.
But Siptu's head of research Manus O'Riordan said today such comparisons had not adjusted for the 2005/2006 depression on private sector pay caused by the large numbers of immigrant workers experiencing a "negative pay differential".
The ESRI's study had also compared weekly earnings rather than annual earnings, which would have included bonuses and irregular payments in the private sector, he said.
Mr O'Riordan said strongly criticised the economic think-tank, claiming it had been as much engaged in campaigning as commentary on the issue of public sector pay.
He said: "The purpose of this paper is to bring about a cool-headed discussion of the sacrifices that everybody has to make, butthose best able to make it are those who have gained most".
"We urgently need to replace the present debate on pay developments, which has been poisoned and bedevilled by both misrepresentations and misunderstandings, with a reasoned alternative that reflects reality."
The union’s research suggested weekly earnings for private sector managers rose from €1,047 in 2005 to €1,188 by the middle of 2009.
In the public sector the figure over the same period increased from €869 to €973, but dropped to €905 when the pension levy was imposed.
Pay for manual workers in private industries increased from €607 to €639 during the period.