Effective Cost Per Mille (eCPM) is currently the most widespread metric used within the mobile advertising ecosystem for publishers to measure the performance of their ads.
For mobile native advertising however, eCPM doesn’t give you the whole picture as a publisher, for 3 major reasons:
- eCPM heavily depends on the interpretation of what constitutes a native impression.
- eCPM can be easily tweaked through the fill rate (as networks are able to serve only high value impressions).
- eCPM makes you lose focus on what matters as a publisher, which is maximizing revenue through a nice user experience (In the end what matters is not the impression, but how good the ad integration drives revenues from your user base while preserving their experience of the app).