Hey guys!

I'd be glad to answer any related MoPub questions here or through the MoPub support email.

There are a number of situations where you will get a lower fill rate. MoPub measures fill rate by impressions trackers fired over requests trackers fired.

What this means is if there is a situation where the ad is firing multiple ad requests (from incorrect integration), but only showing one impression, firing one tracker, a lower fill rate may occur, since this measurement is not a 1:1 ratio. You can see these trackers fire by using a proxy tool like Charles and filtering by MoPub using a proxy to log what network calls are made on your device. This is true for both banners and interstitials.

From my knowledge, AdMob measures their fill rate by ads they serve per request made similarly, but as multiple request trackers may be fired per ad request from incorrectly implementing ads in the MoPub SDK, you may see a difference between AdMob implemented in AdMob mediation and AdMob implemented in MoPub mediation.

There is also the situation where if a publisher shows the interstitial when there is no ad pre-loaded, no ad will be shown. This was done so that users of the app would not have to wait for an interstitial to load. Interstitials should always be preloaded when using MoPub. This also relates to the forum post ArcadEd linked.

For ad units that have been inactive for a while, fill rate may also be low initially if the ad unit is 'warming up'. You should see this messaging in your respective device console logs or log cat logs of your app. What this means is that the ad unit is not on the server which can happen if it gets pushed off the server cache for being inactive. Eventually, the ad unit will not be on any of the servers if it has been inactive. If that ad unit were to receive requests again, the request would propagate the ad unit upon a number of servers, but would not serve an ad for that request. If there is enough traffic, the ad unit will be active again as each server will have the ad unit on its cache. If you are experiencing this issue and are about to push an app live, please contact the MoPub support email and we can help you temporarily push the ad unit to our servers.

Low fill rate can also be the result a number other different types of integration issues. If you would like support on a specific case, please contact us at the MoPub support email.

Thanks,

Edward

To target the ad network to the ad unit you just created, please follow these steps:

1. Go to the "Networks" tab in the MoPub UI

2. Click "Segments"

3. Click the specified segment you want to set (Note: Accounts will automatically be set with a Global Segment on creation. This would be the segment most people would need to navigate to to set the ad network for the specific ad unit. This changes if a new segment is created and has specific targeting as new segments will override the Global Segment for their specific parameters.)

4. There is a filter set to show only running ad sources. You want to close the tab for this that says "Status:Running" inside the filter box to see the rest of the ad sources.

5. Click the drop down for the ad unit you want to change

6. Edit the ecpm of the ad source

7. Click "Set"

This will enable the ad network for that specific ad unit.Edward