Speaking at the Ad Age Data Conference in New York last week, Julie Fleischer said as much as 85% of ad impressions are rejected by the company, Advertising Age reported.
"That's 75% to 85% is either deemed to be fraudulent, unsafe or non-viewable or unknown," she said.
This has become a matter of growing concern for brand advertisers in recent months and Fleischer's comments further raised questions for the industry.
For example, a recent media quality report from Ad Science, the digital advertising intelligence firm, found that about 11% of ad impressions were fraudulent.
"Think about what this means for us as an industry," Fleischer told delegates. "When we're rejecting 75% to 85% of the impressions available, that's a problem," she warned.
Her observation came as Kraft announced that its profits fell nearly 11% to $446m in the third quarter on revenues of $4.4bn and as its CFO Teri List-Stroll confirmed Kraft is looking to improve its advertising effectiveness and to shift adspend to digital.
"We're not looking to drive down advertising costs per se. We're driving for improved advertising effectiveness," she told investors.
"That is to reach the right consumer at the right time in the right medium with the right message. With this focus on effectiveness, we're also realising meaningful efficiencies as we shift our spending to more targeted digital media," she added.
She also confirmed that Kraft's spend on traditional media was down "double-digits" in Q3 2014, but that digital accounted for over 35% of its total spend, up from about 25% a year ago.
Data sourced from Advertising Age, Reuters, Seeking Alpha; additional content by Warc staff