The client trade body said it had been working for three years on a best-practice model for agency remuneration that took into account value and effectiveness.
"In December last year, we felt there had been progress, with ISBA setting out to the IPA a range of ideas for joint initiatives that could help drive change. However, the IPA's stance since then is, at best, unclear," an ISBA statement said.
Campaign revealed that the IPA debated the issue of introducing ratecards at a meeting of council members, but that debate was heated because some agencies believed a ratecard would merely give procurers more clout.
ISBA said the debate was not helped by agencies "seemingly preferring to bury their heads in the sand and 'blame the client' while the market continues to change".
However, it praised agencies who had hired their own procurement professionals "to set out a case for remuneration which rewards properly the value of their services".
Relations between the IPA and ISBA on remuneration are said to have strained because of IPA disquiet over ISBA's practice of sharing accumulated data during members' agency negotiations.
Hamish Pringle, the IPA director-general, said: "The IPA strategy is to embrace procurement, not fight it, and help ensure that we both deliver for marketing."
- Close-Up, p16; Leader, p24.