Two mechanisms, one impression
Mediation is the coordination layer between an app’s ad request and its available sources of demand. The useful question is what that layer does when a request arrives.
Google’s AdMob guide describes bidding as a real-time auction between participating sources. A waterfall instead calls sources in sequence, using the configured average eCPM to determine their order. AdMob also supports a hybrid of the two. These are descriptions of AdMob’s mechanisms, not a claim that every mediation platform implements them identically.
For a publisher, that distinction creates different questions. With a sequence, you need to understand the order and the path through it. With an auction, you need to understand participation and the result. Neither name, on its own, tells you how your players will experience an ad break.
Draw the path before you change it
Our suggested first exercise is deliberately simple: draw one ad opportunity from the app to the final result. Mark where a request starts, where each source is eligible, where a response arrives and where an impression is recorded. Leave blanks where your reporting cannot yet answer a question.
Those blanks are useful. They tell you whether your next move should be a configuration change or better instrumentation. Changing priorities while you cannot see a missing callback makes a comparison much harder to interpret.
- Name the app, format and audience you are investigating.
- Write down the current source order or auction participants.
- Record a baseline for impressions, revenue and the ad experience.
- Keep the previous configuration so you can return to it.
Give one change a fair comparison
Start with a specific hypothesis: a particular source order may work better for one format, for example. Decide what evidence would support that idea before looking at the next report. Keep the audience and date boundaries visible, and note releases or traffic changes that could muddy the comparison.
Treat an ambiguous result as a reason to learn more. A small sample or an interrupted integration is not a useful verdict on an entire mediation strategy. In TionAds, begin by mapping your waterfall and inspecting the reporting around the app you are actually changing.
Give the review an owner and a written decision point. If you adjust two things at once, record both and resist attributing the outcome to only one of them. If the result cannot answer the original question, return to the baseline and design a smaller comparison. A useful experiment leaves you with an explanation that another person can follow, even when the answer is to keep the existing setup.
Further reading
The technical references behind this story. Workflow suggestions are our editorial guidance.