The US Association of National Advertisers’ (ANA) seminal investigation into media agency practices has made tough criticisms of the way they make their money from media owner rebates. But this has also resurfaced claims from Sir Martin Sorrell, chief executive of agency group WPP, that media auditors and consultants have conflicted interests too. To understand whether these claims have substance, we have to look at the history of media auditing.

One of its creators worked in an adjacent office at my first agency and was always testing the concept on us, his media buyers. From the off there was hostility. Media buyers felt that advertisers’ price needs were met by market competition and, frankly, they didn’t much like being checked up on. In those days competition for scarce prime media was great and the major media were the power brokers.

Read the full Marketing Week article here.