The App Attribution Guide
Appendix

Glossary

Every key term in the guide, defined in a sentence or two.

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AdAttributionKit
Apple's newer privacy-preserving attribution framework, available from iOS 17.4, which builds on SKAdNetwork, adds re-engagement and works with alternative app marketplaces as well as the App Store. Read more →
Advanced Mobile Measurement (AMM)
A Meta programme under which, as reported by MMP documentation, advertisers who accept Meta's terms can receive non-aggregated, last-touch attribution data through their MMP. Read more →
Aggregated Event Measurement (AEM)
Meta's own attribution method for iOS 14 and later campaigns, which limits each app to 8 prioritised conversion events and may use statistical modelling where reporting is incomplete. Read more →
App Attribution Partner (AAP)
Google's programme for third-party measurement partners that pass app conversions into Google Ads for attribution and bidding. Read more →
App Tracking Transparency (ATT)
Apple's framework that requires an app to ask for permission before tracking a person across other companies' apps and websites, including before it can read the IDFA. Read more →
apple-app-site-association file
A JSON file hosted on a website's .well-known path that tells iOS which apps may open which links on that domain as universal links. Read more →
Attribution
Crediting an app install, or an action inside the app, to the ad, link or channel that caused it, so marketers know which spend is working. Read more →
Attribution model
The rule that decides how credit is shared between touchpoints. Mobile measurement mostly uses last-touch, where a single touchpoint takes all the credit. Read more →
Attribution window
The longest time allowed between an ad click or view and an install or event for that interaction to receive credit. Also called a lookback window. Read more →
Bot
Software that pretends to be a real user, generating fake clicks, installs or in-app events to collect attribution payouts. Read more →
Click injection
An Android fraud technique in which an app already on the device fires a fake click just before another app's install completes, so the fake click wins under last-click rules. Read more →
Click spam
Fraud that sends large volumes of clicks for people who never tapped an ad, hoping some of them install later so a fake click takes the credit. Also called click flooding. Read more →
Click-through attribution
Credit given to an ad because the person tapped or clicked it before installing or converting. Read more →
Coarse conversion value
A SKAdNetwork value of low, medium or high that an app sets to summarise user activity, and the only value carried in the second and third postbacks. Read more →
Cohort
A group of users who started at the same time, usually by install date, whose behaviour and revenue are compared over the same number of days. Read more →
Conversion value
A number an iOS app sets through SKAdNetwork or AdAttributionKit to describe what a user did after installing, returned to the ad network in a postback when privacy thresholds allow. Read more →
Conversion value schema
A team's mapping of in-app actions to SKAdNetwork conversion values, deciding which behaviours are worth encoding in the limited range available. Read more →
Conversion window
In SKAdNetwork 4 and AdAttributionKit, one of three fixed periods after first launch, days 0 to 2, 3 to 7 and 8 to 35, each of which can produce a postback. Read more →
Cost per action (CPA)
Ad spend divided by the number of times a chosen in-app event, such as a sign-up or purchase, was attributed to the campaign. Read more →
Cost per install (CPI)
Ad spend divided by the number of installs attributed to the campaign. Read more →
Crowd anonymity
Apple's system of tiers, from 0 to 3, that decides how much detail a SKAdNetwork postback contains based on how many similar installs share its attributes. Read more →
Custom URL scheme
A link format such as myapp://path that opens an app directly. It needs no website verification, but other apps can claim the same scheme and there is no web fallback. Read more →
Deterministic attribution
Matching an install to a click using an exact identifier present on both sides, such as a click ID in the Play Install Referrer or a consented advertising ID. Read more →
Device farm
A large set of real phones operated by people or scripts to install apps and complete events at scale, used to collect payouts for installs with no genuine customer. Read more →
Engaged-view conversion
A conversion credited to a video ad that someone watched for a minimum time without clicking; Google requires at least 10 seconds of a skippable ad, or the whole ad if shorter. Read more →
Fine conversion value
A SKAdNetwork value from 0 to 63 that an app can set in the first conversion window to describe user activity in more detail than a coarse value. Read more →
Fingerprinting
Combining device signals such as IP address, model and OS version to identify a device without a dedicated identifier. Apple's App Store policy does not allow it. Read more →
First open
The first launch of an app after it is installed, which most MMPs treat as the moment an install is counted. Read more →
Google advertising ID (GAID)
A resettable advertising identifier on Android devices that attribution systems can use to link ad interactions with installs where it is available. Read more →
Google Play Install Referrer
An Android API that lets an app read, after install, the referrer URL and click and install timestamps Google Play recorded for that install. Read more →
IDFA
Apple's Identifier for Advertisers, a device-level advertising ID that an app can read only after the person grants tracking permission through ATT; otherwise it returns all zeros. Read more →
In-app event
An action a user takes inside an app after installing, such as signing up or buying, recorded and linked to the campaign that drove the install. Read more →
Last-touch attribution
An attribution model that gives all the credit for an install to the most recent eligible touchpoint, usually the last click. Often called last-click attribution. Read more →
Meta Install Referrer
Meta's Android mechanism that lets an app read Meta campaign data for installs from Facebook, Instagram or Audience Network ads, including view-through and multi-session click installs. Read more →
Mobile measurement partner (MMP)
An independent platform that attributes installs and in-app events across every ad network and channel, de-duplicates them and reports results back to networks. Read more →
Non-winning postback
A SKAdNetwork postback sent to an ad network whose ad was considered but did not win the install. It carries no conversion value. Read more →
Organic install
An install that cannot be linked to any qualifying ad or tracked link inside an attribution window, worked out as the remainder after every tracked source is credited. Read more →
Payback period
The number of days until the cumulative revenue from a campaign's install cohort equals what was spent to acquire it. Read more →
Postback
A server-to-server message that reports an install or in-app event to an ad network or partner, so it can credit and optimise its campaigns. Read more →
Probabilistic attribution
Matching an install to a click by statistical likelihood, using non-unique signals such as IP address and device type, which can credit the wrong source. Read more →
Re-attribution
Crediting a returning user's reinstall to a new campaign, usually only once a set period has passed since their last attributed install. Read more →
Re-engagement
Bringing existing users back into an app, typically with a deep link, and crediting their subsequent activity to the campaign that brought them back. Read more →
Reinstall
An install by a person who has had the app before. Some tools count it as a new install, while others apply a re-attribution window first. Read more →
Return on ad spend (ROAS)
Revenue from users attributed to a campaign divided by what the campaign cost, usually measured at a fixed number of days after install. Read more →
SDK
A software development kit; in attribution, the code library added to an app that reports the first open and in-app events to the measurement platform. Read more →
Self-attributing network (SAN)
An ad platform, such as Meta, Google or TikTok, that matches installs to its own ads internally and tells the MMP whether it claims them. Read more →
SKAdNetwork (SKAN)
Apple's privacy-preserving attribution framework, in which the device records ad interactions and installs and sends delayed, aggregated postbacks to ad networks without needing ATT permission. Read more →
Touchpoint
Any recorded interaction between a person and your marketing, such as an ad view, ad click or link tap, that could earn credit for a later install. Read more →
View-through attribution
Credit given to an ad that someone saw but did not tap, if they install within the shorter view-through window. Read more →