The fill rate evaluates the rate at which a publisher has successfully sent and received a request for a full ad impression from an ad network. If the request isn’t successful, the user will encounter an empty black space in the publisher’s app where the ad should be display.
The fill rate formula
To calculate the fill rate, you can divide the total number of times an ad was successfully displayed by the total number of times the ad was requested.
For example, if you’ve given advertisers 100,000 spots in your inventory to fill with ads but 100 failed to displayed, the fill rate would be (100,000-100)/100,000, or 99.9%.
However the fill rate concept is slightly more complicated than the simplified explanation provided above, not to mention that it’s often misunderstood. To decipher what a “fill rate” actually means, we’ll look at why the fill rate exists.
Why is the fill rate important?
If we’re talking about fill rates as it applies to an ad campaign, the metric calculates the percentage of “wasted” inventory. Realistically, 100% of the ads requested by publishers in an ad network won’t successfully display for various technical reasons. But having a fill rate as close to 100% is vital if a publisher wants to maximize the chance that their users will click on an ad. Every ad that fails to display in a pulbisher’s app is the possibility that they’ve missed out on ad revenue. After all, a user can’t click on an ad that hasn’t fully loaded.
Why do ad creatives fail to display in the first place?
Fill rate issues can boil down to one or more technical problems at any one time. These problems may not occur frequently, and generally an ad network’s fill rate should be more than 90%, but complications will happen from time-to-time.
One of these problems might occur when too many publishers are requesting a single advertiser’s ad at once. The ad network’s servers might overload as a result and delay the delivery of the requested ad. Or the issue could even be as simple as a connectivity failure. For instance if the user has limited access to the Internet, it may be impossible to serve a complete ad. The same user might even decide that the ad is loading too slowly and exit the ad before the creative fully loads.
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