The Adjust Mobile Measurement Glossary



What is the Identifier for Advertisers?

The Identifier for Advertisers (known as the IDFA) is a random device identifier assigned by Apple to a user’s device. Advertisers use this identifier to track data so they can deliver customized advertising.

The IDFA reveals no personal information. Instead, it’s used for tracking and identifying a user, which then allows advertisers to access aggregated data which can be used to discover information – such as which in-app events they trigger.

The IDFA can also identify users when they interact with a mobile advertising campaign, provided the channel offers IDFA tracking and that the advertiser tracks users who interact with adverts successfully. If this occurs the IDFA can pickup whether specific users click an advert for payment and attribution purposes.

Why is the Identity for Advertiser important?

IDFAs are important to advertisers because they are an accurate means to track iOS users. By assigning a device to a single IDFA, advertisers who are able to track IDFAs within a campaign have much greater certainty about the defining qualities of that user and whether they installed due to an advertising campaign.

IDFAs also offer a welcome level of privacy for users. This can have a additional effects for advertisers, but the IDFAs depersonalization of user data ensures that it is on the right side of data protection efforts – preventing advertisers from becoming embroiled in data privacy problems.

Identity for Advertisers and Adjust

IDFAs are one of the most precise ways to track a mobile advertising campaign on iOS, but users are increasingly opting out of using it.

Apple introduced a way for users to show that they didn’t want to be tracked. By activating an option called ‘limit ad tracking’ (or LAT), user information would be shown as blank, and as such those users couldn’t be shown targeted ads. As it stands, roughly 20 percent of iOS users cannot be tracked using the IDFA, as 1/5th of users have enabled LAT.

Adjust can track users who do consent to companies accessing their IDFA and the associated data. IDFAs can be tracked using Adjust’s tracker URLs to help advertisers segment their users. Adjust also offers attribution services for Apple’s Search Ads, which exist exclusively on iOS and will only include users who have the IDFA activated.

Furthermore, marketers can use Adjust’s Privacy Insights to understand how many users have activated LAT. By using one-way cryptographic hashing to identify LAT usage without identifying anything about the user, we can help marketers to spot users who limit tracking so they can see its impact on the audience for their iOS app in full.