About AdMob mediation groups

What is AdMob Mediation?

Mediation is a capability of AdMob that helps you manage all of the ad sources that you use to serve ads to your apps in one place. Using mediation, you can send incoming ad requests to multiple ad sources and help ensure that you find the best available ad sources to fill the requests. Mediation will use mediation groups to try to help maximise your revenue by ranking all the ad sources based on optimised performance.

What are mediation groups?

Mediation groups are combinations of targeting settings that help to optimise the revenue generated by your ad units. You can create mediation groups ahead of time, then add ad units and ad sources as you go, or create them all at once. Instead of setting mediation options for each ad unit repeatedly, you can just set them once for your mediation groups, then add your ad units to the groups that you want.

To find your mediation groups page, sign in to your AdMob account and click Mediation in the sidebar.

Once you've set up mediation in AdMob, you can use the Google Developers guide (Android, iOS) to implement mediation in your apps.

How do mediation groups work?

When an ad request is sent to AdMob from one of your ad units, AdMob Mediation examines the ad request and compares it to the targeting settings of the mediation groups that you've defined.

• If the request matches the targeting for one of your mediation groups, that group will fill the ad request by serving an ad from one of its included ad sources.
• If the request matches more than one of your mediation groups, AdMob will use the group priority to determine which group should fill the ad request. Conflicts between mediation groups should be avoided, if possible.
• If the request doesn't match any of your mediation groups, it will be automatically filled by the AdMob (default) group, instead.

What is mediation group priority?

Priority tells AdMob which mediation group is more important to your revenue goals. When multiple mediation groups can be used to fill an ad request, AdMob uses the value in the Priority column to determine which mediation group should fill the ad request.

There are a few things to keep in mind when setting priority: 

• When more than one mediation group matches the targeting of an ad request (location, platform, etc.), the mediation group with the highest priority (the smallest number) will be chosen to fill the ad request.
• The highest priority that you can set is 1. 
• The lowest priority that you can set is the number equal to the number of mediation groups that you’ve created. Example: If you have 5 mediation groups, 5 is the lowest priority you can set. If you set priority to 8, it will automatically default to 5.

After an ad request is matched to a mediation group, the ad request will waterfall through that group's ad sources.

Example

Ad request from a Canadian Android user:

 

AdMob receives an ad request from an Android user in Vancouver, Canada. The ad request matches 3 of the publisher's mediation groups: 

 

• 'Banner ads for Android in North America' (priority 3, uses InMobi, Flurry and the AdMob Network)
• 'Banner ads for Android worldwide' (priority 5, uses AdFalcon, Flurry and the AdMob Network)
• 'Banner ads for Android in Canada' (priority 1, uses Flurry, Chartboost and the AdMob Network)

 

The mediation group 'Banner ads for Android in Canada' will be chosen to serve the ad because its priority is 1, which is higher than the priorities of the other conflicting groups. The ad request will waterfall through the ad sources included in the mediation group: Flurry Chartboost the AdMob Network.

How do bidding and waterfall ad sources work together in a mediation group?

When you use both bidding and waterfall ad sources in a single mediation group, this is a hybrid setup. When the ad request is matched to your mediation group, the bidding auction occurs in real time. The bidding ad source that wins the auction is then placed in the mediation waterfall alongside your waterfall ad sources. 

If the bidding ad source that won the auction is placed first in the mediation waterfall, it will get the opportunity to serve the ad. However, if the bidding ad source is not the highest eCPM in the mediation waterfall, the waterfall ad sources will be called first. 

Example

In this example, Exchange B wins the bidding auction with a £4 bid and is placed according to its eCPM value in the mediation waterfall. However, Network 1 has a higher eCPM value (£5) than the winning bid from Exchange B. Therefore, Exchange B is placed second in the waterfall.

From now on, the waterfall functions normally. Network 1 serves the ad if it has one. If not, Exchange B will get the opportunity to serve the ad.

Avoid conflict between mediation groups

You can avoid conflict by planning ahead. If you target a country or region, platform, or ad format explicitly in one mediation group, you may want to exclude it from the other mediation groups that you create. 

In the example above, the publisher had already created a specialised group that targeted banner ad requests from Canadian Android users. They could have avoided conflict between groups by excluding Canada from the other Android banner ad mediation groups.

However, if you create many mediation groups to manage your ad sources, there will probably be conflict on occasion. It's important to consider the correct priority for your mediation groups to help ensure that AdMob can use them to try to maximise your revenue efficiently. 

AdMob (default) group

In most cases, an ad request received by AdMob will be compared to your mediation groups and filled by the group with the matching criteria. However, some ad requests won't match any of your mediation groups.

The AdMob (default) group automatically tries to fill any ad requests that aren't matched to any of your mediation groups. It sources ads directly from the AdMob Network.

The AdMob (default) group is already created for you in the Mediation groups tab.