To prepare for cookies deprecation, Webedia integrated the Prebid Identity Module with ID5, The Trade Desk, and Criteo ID as ID providers.
To measure the identity module’s effect on their header bidding setup, they decided to use Pubstack to conduct A/B tests at scale through the Pubstack analytics dashboard and determine the incremental value of using an identity provider.
Webedia’s Ad Stack:
This part will take you through the A/B test analysis results, whose goal was to compute identity providers’ predictive uplift on publishers’ advertising revenues.
The goal here is to check if:
a- having an ID in the ad call allows Prebid to bid more often
b- the said bid has a higher CPM than when there is no ID in the ad call
To verify this, we’ve used the BPM metric, which calculates the value of the bids won by Prebid on the total number of auctions. This shows the real impact of identity without considering the competition outside Prebid (AdX, TAM, direct campaigns,…).
From the graph above, we can see an uplift between 3,5% and 10% of BPM for the test population vs. the control population. This uplift can be due to two factors: an uplift in Prebid Bid Rate or an uplift in CPM.
As we can see from the graphs above, the CPM has no impact on the BPM uplift; it remains neutral whether there is an ID in the ad call or not.
To sum up this first part on Prebid bidding, we can conclude that:
The goal here is to check if having an ID in the ad call allows Prebid to generate more ad revenues.
To verify this, we will use the RPM metric, which represents the prebid revenue for 1000 auctions. We will also use the CVR, which represents the ability of prebid to win an auction when confronted with the competition (ad server, tam, direct campaigns,…)
The graph above shows an uplift between 5% and 10% in prebid revenues for the test population vs. the control population. This uplift can be due to two factors: an uplift in CVR or an uplift in BPM.
After digging more in the data, we found out that there was only a slight uplift in CVR and that the uplift mainly comes from the BPM metric, which confirms further that Prebid bids more often when there is an ID in the ad call.
Identity has minimal impact on the ability of Prebid to win bids against the competition.
From the findings above, we can conclude that:
We’ve pushed things a little further and wanted to know if there was a significant impact depending on the browser.
From the graphs above, we can see that:
We’ve tried to assess the impact of identity by bidder, but the results were not very conclusive. Probably because we couldn’t discriminate by ID provider, this hypothesis will be verified in future research.
If there were only four learnings to take from this survey, we would sum it up as follows:
Ines Mouadil, Programmatic Operations Manager at Webedia, says:
“We are delighted to have worked with Pubstack on one of the first analyses of Prebid’s Identity Module. The results of this A/B test and the uplift in our programmatic revenues have confirmed the need to work with Identity in the programmatic chain. From a publisher’s perspective, we could never have measured this impact on our own without the help of Pubstack”.
If you want to have more details about the study, please watch here our webinar, where our Senior Data Analyst Adrien Rouget and Programmatic Operations Manager Inès Mouadil from Webedia are sharing the results. And if you are interested in understanding the impact on your own ad revenue please feel free to book a meeting with a Pubstack expert here.
To continue on the topic of identity, we’ve written a topic to help you learn cohabiting with Adblockers.
We’ve also ran a detailed statistical study on the impact of your CMP window on ad revenue, made possible thanks to our Analytics module. If you want to read the study you can find it here : How To Optimize Your CMP For More Ad Revenues