The study, by consulting firm Foote Partners, found that ITers with supplier qualifications maintained the same level of bonuses during 2001 and the first quarter of 2002, whereas those without experienced a decline.
Non-certified ITers have seen their bonuses fall from a high of 10.2% in the third quarter of 2000 down to current levels of 8.1%.
Some 59% of those with supplier qualifications received a pay rise within the first year of attaining their primary certification. The ITers that have benefited most have been those with project management, database and security qualifications.
David Foote, president of Foote Partners, believes employers' current preference for supplier certification is partly due to the fact that it guarantees a certain level of knowledge in the specified area. However, the survey also revealed that supplier-neutral qualifications are slowly catching on.
Although certification is becoming more common, it has not yet reached the point where all UK employers regard it as essential.
"It is not a prerequisite for a lot of IT jobs," says Tony Poulson, partner at recruitment agency Spider-iT. "It is very technology-dependent.
"With Cisco you can pretty much work out what salary you should be on depending on your level of accreditation, whereas this is not at all true for Oracle."
However, Poulson does believe that an increasing number of employers are now looking for vocational qualifications, whether supplier-certified or not.