Why comparing eCPMs can lead you to compare apples and tomatoes?

   tomatoes-712955_960_720

Some developers are using the eCPM metric to compare the performance of ad networks. Let’s take the example of a developer who is testing 2 ad networks.
On network 1, he gets a $2 eCPM.
On network 2, he gets a $3 eCPM
It could be tempting for this developer to conclude that network 2 is better.

The problem is that if you do that, you are most likely comparing things that are completely different by essence.

If you are sending Eastern Europe traffic to network 1 and US traffic to network 2, it’s quite normal that the performance is not the same. The reason for that is that advertisers are willing to pay more for US than for Polish traffic. Generally speaking, there is a high chance that your traffic breakdown per country evolves over time so you won’t be comparing the same thing if the 2 tests are not conducted at the exact same time.

eCPM is nice but revenue is better!

I have talked to several developers who were reluctant to display ads if their eCPM was too low. They were simply thinking it was not worth the shot. However, a developer who has a lot of traffic in countries where advertisers propose low payouts can still make significant revenues ! So low eCPM doesn’t mean necessary low revenues !

So what other things you should look at when choosing an ad network ?
I will discuss this in my next post. Stay tuned!