In its critical agency report, The Association of National Advertisers (ANA) didnt touch on the complexities of the modern media-buying landscape, said Rob Norman, chief digital officer of WPP’s media-buying arm GroupM, in a blog post Tuesday.

Norman’s response comes after the ANA mic-dropped its investigative report into agency transparency, criticizing agencies for taking rebates and a principal on media and for directing spend toward vendors where agencies have equity stakes.

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