Ad impressions is a term to describe each time a mobile ad is displayed within an app. This is a diagnostic statistic independent from any form of engagement and simply refers to whether the ad has been shown.
Ad impressions are the backbone of the mobile advertising space and are commonly used across campaigns of all variations and goals. Alone, ad impressions offer both publishers and advertisers an insight into how many times it has been shown. However, when analyzed alongside other metrics, impressions become an essential part of understanding a campaign’s effectiveness.
In addition, ad impressions are used for the basis of most mobile advertising pricing models. Impressions play a part in helping advertisers calculate the cost of a campaign based and allowing publishers to understand how much revenue they can get from displaying a certain number of impressions.
The full value of ad impressions as an advertising statistic is when they are used in conjunction with other metrics like revenue and clicks. In doing so, you can gain a deeper insight and properly evaluate the performance of an advertising campaign. Some formulas which rely on ad impressions include:
CPM: Cost-per-mile, which is a pricing model in which advertisers can pay for ads in bulks of 1,000 ad impressions.
The formula for CPM is CPM=Ad Spend ÷Impressions ×1000
eCPM: effective cost-per-mile, which is a parameter publishers can use to understand how much revenue they will get from each 1,000 ad impressions and better gauge how well an app can be monetized.
The formula for eCPM is eCPM=Total Advertising Revenue ÷Impressions ×1000
CTR: click-through-rate, which is a formula that calculates the percentage of users which clicked on an advertisement.
The formula for CTR is CTR=(Clicks÷Impressions)×100
Ad impressions are sometimes confused with ad clicks and reach. The difference between the three is subtle, but important. As mentioned above, ad impressions refer to the number of times an ad has been shown on an app. Ad reach refers to the number of unique users who have seen the ad. For example, if an ad has 300 impressions but each user saw the same ad 3 times, the reach would be 100. Clicks, on the other hand, refer to the number of times a user has clicked on the advertisement. Ad clicks are therefore an engagement metric and are used in several other formulas, including CPC (cost-per-click) and CR (conversion rate).