While compliance is a challenge, there is some good news to report. Publisher rates for visitors providing consent are leading to higher CPMs.
When visitors provide affirmative consent, you can trust the data. First-party authenticated user data allows you to customize content and marketing, thereby creating a better experience for the consumer and premium inventory for the publisher.
A study published in Ad Exchanger reported ad rates for publishers using a CMP saw an overall  9% lift in CPMs and a 5% increase in fill rates post-GDPR. Those publishers that did not use a CMP saw ad rates drop precipitously.
Publishers without CMPs lost the ability to track ads effectively and saw CPMs drop by more than 40% and fill rates fell by more than 30%.
Publishers implementing a CMP rather than sticking with what they already had in place saw the biggest benefits. CPMs grew by 52% and fill rates increased by a third.