What is an ad impression?

An ad impression (also known as a view-through) is when a user sees an advertisement. In practice, an impression occurs any time a user opens an app or website and an ad is visible. Each time an ad is served and viewed, it is counted as an impression. Impressions are not to be confused with  engagements.

An Impression occurs when a user sees an ad, but it doesn’t imply engagement. A click happens when the user actually  clicks on the ad. While clicks are more valuable for direct measurement of conversions, impressions help measure ad visibility and can have a significant impact on campaign uplift and performance. 

Ad reach differs from impressions by measuring how many unique users see your ad, providing a clearer picture of how many people have been shown your campaign..

Ad impressions are essential in mobile advertising. Mainly measured when working with a cost per mille (CPM) model—where advertisers pay for every thousand impressions served—advertisers use impressions to evaluate ad reach across channels and optimize campaigns, while publishers use them to calculate effective cost per mille (eCPM) and maximize revenue. Accurate impression measurement is critical for calculating metrics like click-through rate (CTR).

Additionally, impression data can help mobile marketers drive improved user acquisition (UA). More ad views mean greater exposure to potential users. For example, if you’re promoting a mobile game and running in-app banner ads targeted at casual gamers, measuring impressions lets you see how often your ad is displayed within other gaming apps. This helps you assess whether the ads are being shown to the right audience and allows you to adjust pricing, placements, or creatives to boost visibility and installs.

App store optimization (ASO) also benefits from impression data. If ad views are high but downloads are low, it signals a need for improvements in metadata like app store title or description. Marketers can optimize these elements to boost ad visibility and acquire more users.

While ‘impressions’ broadly refers to ad views, ad impressions do vary somewhat in how they measure visibility and interaction with ads. Here's a breakdown of the key types:

• Served impressions: These occur when an ad is delivered to a web page, regardless of whether the user sees it. This is the most common way to measure impressions and serves as a baseline metric for ad reach. However, served impressions may include ads that are not visible, potentially overstating how many users actually see the ad.
• Viewable impressions: These measure the number of times the target audience actually sees an ad. According to the Media Rating Council and Interactive Advertising Bureau, an ad is considered viewable if at least 50% of it is visible on an active browser tab for at least one second. This type of impression provides more accurate data on ad visibility but can be harder to measure, as not all ad servers count viewable impressions.
• Verified impressions: These confirm whether an ad was shown to a real user, reducing the risk of fraud. For advertisers, verified impressions ensure that ads are not being delivered to bots or non-human traffic.
• Engagement impressions measure how often users interact with an ad, including actions like expanding the ad or clicking on elements within it. Engagement impressions help advertisers assess which ads generate the most user interaction and interest. This can also refer to video impressions where the content was viewed for a specific period of time (like 10 seconds) implying the impression was an ‘engaged’ one.

 

Adjust provides impression measurement as an opt-in feature. We use advanced attribution models that differentiate between impressions and clicks. When an Adjust tracker is linked to an ad network in the Campaign Lab, Adjust generates two unique URLs for each campaign: click-based attribution and impression-based attribution. This setup offers a comprehensive view of your app’s conversion funnel. Adjust also offers a customizable attribution window of up to 24 hours, enabling marketers to accurately attribute installs to impressions.

Adjust’s view-through attribution (VTA) goes a step further by enabling you to measure impressions that lead—or provide assistance—to installs, even without direct engagement. For example, higher ad exposure on channel A might result in increased conversions on channel B.This insight means you can confidently make budget allocation and campaign optimization decisions, as well as adjustments to your attribution window based on data and goals.

For more detailed insights, download our ebook, Gaining visibility with view-through attribution: A mobile marketer’s playbook.

Adjust also supports impression-level ad revenue measurement. With Adjust’s reporting and MAX by AppLovin's impression-level revenue data, marketers can accurately compare ad revenue with UA costs. Adjust also enables revenue measurement at aggregated and impression levels, helping publishers analyze ad revenue per thousand impressions (RPM) and user lifetime value (LTV). Real-time revenue analysis is available through API and SDK integrations with ad networks, providing deeper insights for monetization optimization.

Discover how Adjust can help you measure and optimize your app’s performance. Request a demo today!