Mobile Ad Formats Lab #2 — Banner Ads Metrics & Insights

In our first article in Mobile Ad Formats Lab series we discussed the pros and cons of using banner ads in mobile apps, not only from the perspective of the app publisher but also from the side of the marketer.

In this article we will continue looking into banner ads. We will see some important metrics that app publishers need to know when dealing with banner ads and also some insights on how app users perceive banner ads and their usage within mobile apps.


Ad Impression

An impression is a metric used to quantify the display of an advertisement in a banner ad and is calculated on the time the ad is displayed. Counting an ad impression is relevant to viewability and whether that ad was eventually shown to a user or not. In some ad networks you can see ad impressions categorized as eligible or not.

Ad Clicks

The number of times a user clicked on an ad.

Ad Requests

The number of times a user requested to receive an ad.

Ad Viewability

Viewability of an ad is defined by the Media Rating Council (MRC) and has to meet the two following requirements:

  • Pixel Requirement: Greater than or equal to 50% of the pixels in the advertisement has to be visible on the screen.
  • Time Requirement: The time the pixel requirement is met was greater than or equal to one continuous second, post ad render.

Viewability of an ad usually helps categorize ad impressions to eligible or not.


eCPM which stands for effective cost per mile, is what a publisher will earn for every one thousand ad impressions.

eCPM=(Total Earnings/Total Impressions) * 1000

App developers use eCPM to compare ad revenue generated, across multiple variables such as ad networks, regions, geos, OS and others.

In some ad networks like AdMob, the term RPM is used which stands for revenue per mile. This terminology is more relevant to the publisher side since it calculates the average revenue per thousand ad impressions.

Fill Rate

Fill rate is the percentage of number of delivered ads per number of ad requests. In some cases like in AdMob this is called Match Rate.


Effectiveness of banner ads is measured by click CTR (click through rate). Click through rate is the percentage of people who clicked on a banner ad after seeing it. Bear in mind that even if this metric can be easy to calculate, metrics are not the end all be all of it. They could be misleading and not reliable due to to the high rate of accidental clicks on mobile.

CTR=(Number of click-throughs/Number of Impressions) * 100 (%)

In many cases new metrics are used to evaluate the CTR which involve the engagement of the user after the initial click.


We have already seen what app publishers and marketers think of banner ads but what about the end-users? With the help of Pollfish, a DIY survey tool with access to millions of mobile users we surveyed more than 500 Android app users and asked several questions around banner ads. Below we can see some really useful insights on how users perceive banner ads and their usage within mobile apps. Full survey results can be found here.


Accidental Clicks

More than 91% of the users that saw and clicked in the past on a banner ad claimed that at least one of the clicks was accidental. This number actually demonstrates one of the major pains in banner ads world, as we have discussed in the previous article, which is the increased number of accidental clicks that happen usually on mobile and results to false click through rates.


Publishers try to trick users to click

The most interesting question in the survey asks users if they feel that an app owner ever tried to trick or mislead them in order to click on a banner ad. Almost 67% of the users responded that they do feel that app publishers tried to mislead them in the past! This is another major issue in the banner ads world and ad networks in an effort to overcome this, they try to apply strict policies to avoid mis-practises by app publishers that lead to false CTRs.


Ads are not relevant to users

More than 43% of the users think that the content they see in banner ads is not relevant to them. This is something that can explain partially the low click through rates but it is also something expected to change in the near future with the adoption and more proper usage of programmatic.


Users try to opt-out from specific banner ads

In another question, users were asked if they have ever clicked on an ad to ask stop seeing it. Some ad networks like AdMob offer this option while users are also asked to provide feedback on why they want the particular ad to stop being shown to them.

More than 73% of the users claimed that they have used this option in the past.

Where do users prefer to see a banner ad in a mobile game?

Aside from the most obvious and expected answer, that nowhere is a good place to show a banner ad (or an ad in general), more than 27% of the users chose as as the most preferred placement for seeing a banner ad in a mobile game, the screen between levels.

The next most popular choice was the app’s initial screen with more than 18%. From the chosen answers we can understand that users prefer not to see an advertisement in the main game screen and prefer to compromise and see banner ads outside of the main experience of the app.

To sum up, there are several important metrics that app publishers should get familiar with when dealing with banner ads in their mobile applications. Understanding the terms and metrics will help them not only measure the performance of banner ads but also use them to compare the performance in different ad networks, ad formats, geos and others.

In the next article we will examine several best practises along with things to avoid when using banner ads in mobile apps in an effort to increase the performance and engagement of those ads, while staying aligned with ad networks policies.