You can set an eCPM floor (also known as a minimum eCPM) for each of your ad units. By setting an eCPM floor, you're instructing the AdMob Network not to serve ads to that ad unit that are below the minimum eCPM you've set.
Setting an eCPM floor is likely to affect overall monetization. A higher eCPM floor value will likely cause a decrease n an ad unit’s fill rate. You should monitor the eCPM floor placement with other ad networks to make sure you're maximizing total revenue.
How it works
When you set an eCPM floor value for an ad unit, the AdMob Network will serve an ad only if the
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