Revenue per Eligible Opportunity: The Ad Metric That Fill Rate and eCPM Miss
eCPM ignores unfilled requests; fill rate ignores price. Revenue per eligible opportunity counts both — which is why it is the right scorecard for floors, networks and bidding migrations.
What is revenue per eligible opportunity?
It is ad revenue divided by the number of moments where a placement was eligible to show an ad — whether or not an ad was requested, filled or shown. It combines the three things that decide ad yield (how often an opportunity fills, how often a filled ad is shown, and what it earns) into one number that is hard to game.
Why not just use eCPM or fill rate?
Because each moves in the “right” direction for the wrong reasons:
- eCPM rises when you raise floors, because cheaper impressions stop clearing. The impressions you lost do not appear in the metric at all.
- Fill rate rises when you lower floors or add low-priced demand. More opportunities clear, but not necessarily for more money.
When we moved from waterfall to bidding, fill improved first. Revenue per eligible opportunity did not move at the same rate. That was the useful signal: more opportunities were clearing, but the additional fills were not creating proportional revenue.
How do you define an eligible opportunity?
At the placement trigger in the game, not at the ad request. A rewarded video offer that appeared on screen, an interstitial slot the player reached, a banner-visible second. Defining it at the request level lets SDK and caching behaviour leak into the denominator. Whatever you choose, keep it stable, or trends will reflect definition changes.
When should you use it?
- Floor changes. A floor is a minimum clearing price, not a quality filter. Judge it by whether revenue per eligible opportunity rose, not whether eCPM did. The Floor Price Simulator shows why the two diverge.
- Adding or removing a network. A new source that wins rarely but adds latency can lower the number even with a high reported eCPM.
- Waterfall-to-bidding migrations and mediation switches. Compare the same placements before and after, by geo and platform.
- Placement design. Two placements can have identical eCPMs and very different value per opportunity if one is shown far more reliably.
What does it not tell you?
It does not include the cost of the ad to the player. A placement can maximise revenue per opportunity and still damage retention or purchases. Pair it with the guardrails you set before the change — see monetization test guardrails.
Related: Fill Rate Is Not a Strategy · Network Revenue Quality Is More Than eCPM · Glossary: fill rate