We already wrote here a few times about eCPM decay and some of our tips were also quoted in other places. In this post we are going to talk about another type of eCPM decay – the one that is rarely mentioned. I’m talking about the trend of eCPM going down as a function of how long the user was retained in the game as opposed to the decay that happens as a result of high frequency of ads during the day.
First Test – How eCPM behaves over the life of a user
In this test we looked for users who started playing the game in a certain month and than checked their eCPM in that same month versus the eCPM in the following month and the third month. We did this test across many games to make sure the results are not isolated to a single game. In this chart below you can see the average values, the maximal ones (the game with the highest rate in that month) and the minimal ones (the game with the lowest rate in that month) across all the games we tested. Note that this test was done only with US based users and only in the following ad formats: Offer walls, Rewarded Videos and Interstitials.
There is clearly a trend here. The eCPM is going down the longer the user is retained in the game. In fact, new users can have 2x or more the eCPM of loyal users. We can attempt to explain this finding of course. One assumption is that the same behavior pattern that impacts eCPM decay also comes into play here. Users tend to grow tired of advertising. However, here the situation is a bit different. Consider the case of a user who downloaded a new game this month but might also downloaded another game 3 months ago. It’s the same user so why is he responding better to ads in the new game he downloaded vs. the older game? The answer could be that the user gets tired of ads in a given context seperately. He might learn where the ads are placed and his brain is getting trained better to ignore them. It will be interesting to see what happens if we mix up the ad placements for loyal users to see if we can engage them with the ads again.
Second Test – Does it matter where the user came from?
Here, we tried to see if a user that came organically behaves differently compared to a user that came through paid UA or cross promotion. We compared only for US based users – here is what we found.
So it looks like the Cross-promo traffic had very high eCPMs in the first month. Paid installs that came from Facebook also appeared higher than Organic. However, the drastic difference in the eCPM of the usres in the 1st month almost vanished when looking at the the 2nd and 3rd month. Specifically, the cross-promo installs were lower compared to organic installs in the 3rd month. In general, the eCPMs converge to the same levels almost. It seems that the impact of the source of the user only lasts for the first month and after that month the user ‘forgets’ where he came from and users behave in a similar fashion. It’s possible that users who came from an ad into your game are more likely to respond to ads in your game. The fact that the impact only lasts for 1 month could potentially be explained by users response to ads is a temporary behavior and not a long lasting behavior pattern.
Third Test – Do we see the same trend across all ad formats?
We wanted to see if all ad formats behave the same way when it comes to this type of eCPM decay. Do users lose their interest in rewarded videos the same way as they do with interstitials? We compared 3 ad formats and this time we compared not just US traffic but we allowed international traffic. To make it easier to follow we indexed the results so they all fit in the same scale.
It’s easy to notice that the findings are consistent across all ad formats we tested. We didn’t check banners and native ads in this study. It’s possible we will do another post specifically focused on that.
Optimizing for the long retained users
One conclusion from this data is that there should be opportunities to better serve ads for loyal users so they monetize better. Here are some ideas to consider specifically for this segment:
- Serving ads through SSPs – these ads come with an upfront bid price and are less influenced by users’ ad engagement
- Closing fixed CPM deals for this segment
- Mixing it up – changing the placements for user who have been playing the game long enough
The impact on LTV calculations
These findings might also impact how companies think about LTV prediction. Many LTV models assume that eCPMs and ARPDAU are not influenced by the amount of time the user played the game. If your existing model is predicting LTV based on the 1st month’S eCPM the actual result might be worse than the predicted LTV.
What about Apps
While the reseacrch was focused on games only we expect that to find the same patterns in Apps. At least that is true for the formats we checked: Rewarded videos, Offer walls and Interstitials.