Understanding Fill Rate

Throughout the mobile advertising world, you often come across the term 'fill rate'.  What does it mean and how can you use it to generate more revenue from your apps?

What is Fill Rate?

Fill rate is the number of ad requests answered (ad response), divided by the number of ad requests sent (requests answered/requests sent). Shown as a percentage, the fill rate allows you to make sure that you are taking advantage of every opportunity to display an ad in your app.

A 100% fill rate is an ideal situation, but it is very difficult to achieve. Network errors, timeouts and users leaving a page/app before the ad is delivered are usually reasons why a perfect 100% fill rate rarely happens. 

Note that fill rate can change over time as it depends on our ad inventory in each country. Start.io (formerly StartApp) usually has a very high fill rate due to the wide variety of advertisers and ad placements available.

How does Fill Rate affect eCPM?

A high fill rate indicates that ad responses were delivered regardless of the eCPM of the ad. This gives publishers a better chance of earning greater revenues by displaying as many ads as possible in the desired integrated placements, seizing all opportunities to show ads.

Since more ads are displayed when having a high fill rate, more impressions are generated and therefore it is possible for the eCPM measurement to decrease.

How to find Fill Rate in your Start.io (formerly StartApp) account

You can find fill rate as part of your analytics and custom reports as a way to measure your account's performance.  You can look at overall fill rate, by country, app, or ad type.

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