Impression-to-Install Rate

CPI stands for Cost Per Install, meaning the cost that an advertiser pays each time a user installs their mobile app after clicking on an ad. CPI is a performance-based pricing model, which means that the advertiser only pays for results that directly contribute to their business goals, such as app installations. This pricing model is particularly popular among mobile app developers who want to promote their apps and acquire new users.

Cost Per Mille (CPM), also known as cost per thousand impressions, is an advertising pricing model where advertisers pay a fixed rate for every 1,000 times their ad is displayed to users. "Mille" is Latin for thousand. CPM is one of the most common buying models in digital advertising, particularly for brand awareness campaigns and display advertising. In the mobile app ecosystem, CPM is used both by app developers buying ads to acquire users and by app publishers selling ad inventory within their apps. For user acquisition, CPM campaigns are typically less performance-oriented than CPI or CPA models, since the advertiser pays for visibility rather than a specific action. However, CPM can be effective for reaching large audiences at scale and building brand recognition. For app publishers monetizing with ads, CPM represents the revenue earned per 1,000 ad impressions served — also called eCPM (effective CPM) — and is a core metric for evaluating ad monetization performance across different ad networks and formats.

Creative fatigue occurs when an advertising audience has been exposed to the same ad creative too many times, resulting in declining click-through rates, rising cost per install, and diminishing campaign performance. In mobile user acquisition, creative fatigue is one of the most common reasons for campaign degradation over time. As users see the same images, videos, or messaging repeatedly, they begin to ignore the ads — a phenomenon sometimes called "ad blindness." Detecting creative fatigue early is critical for maintaining efficient UA spend. Key indicators include a decline in CTR while impressions remain stable, rising CPIs, and lower conversion rates from impression to install. Growth teams combat creative fatigue by maintaining a pipeline of fresh creatives, systematically rotating ad variations, testing new concepts and formats, and segmenting audiences to control frequency exposure. Apps running web funnel campaigns face similar dynamics — landing page designs and value propositions must be periodically refreshed to sustain conversion rates.

App Store Optimization (ASO) is the process of improving the visibility and conversion rate of a mobile app within app store search results and browse pages. ASO encompasses keyword research and optimization of app metadata — including the app title, subtitle, keyword field, and description — as well as optimizing visual assets like the app icon, screenshots, and preview videos. The goal is to increase organic discovery so that more users find and install the app without paid advertising. ASO also includes ongoing efforts like localizing listings for different markets, encouraging positive reviews, and monitoring category rankings. For subscription apps, ASO directly impacts customer acquisition cost (CAC), since higher organic visibility means a greater share of installs come at zero marginal cost. Effective ASO requires treating the app store listing like a conversion funnel: first capturing impressions through keyword relevance, then converting those impressions into page views through compelling icons and titles, and finally converting page views into installs through persuasive screenshots, descriptions, and social proof.

Mobile app conversion rate (CR or CVR) is the percentage of users who achieve a specific goal within the app, such as making a purchase, creating an account, subscribing to a service, or completing a survey. Conversion rates are an important metric for mobile app developers and marketers as they indicate the effectiveness of the app in driving user engagement and achieving business goals. A higher conversion rate typically means that the app is successfully guiding users towards the desired action, while a lower conversion rate may indicate that there are issues with the user experience or the app's marketing strategy.