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The advertiser identifier is a distinctive and randomly generated device identifier that Apple assigns to a user’s device. Let’s understand the role it plays and its relevance after the rollout of iOS 14.5.

IDFA Full Form

The full form of IDFA is identifier for advertisers. IDFA helps advertisers to target and track users within apps on iOS devices. They can use this device ID to measure a particular campaign and understand the user journeys. This further aids them in delivering customised advertising.

IDFAs do not reveal the personal information of users and only provide app marketers with data in the aggregate. It can be used to gain a better understanding of the types of users using the different sources of a campaign, helping in its precise optimisation and development of a data-driven user acquisition strategy.

An IDFA is usually tied to devices instead of browsers, and it enables an advertiser to get notified when a user of a phone has taken an action by using their ad in a browser and then installing, using, or interacting with ads in their app.

What is the Importance of IDFA?

IDFAs play an integral role in letting marketers know about their target audience and the way said audience interacts with marketing campaigns. They help in accurately tracking an iOS user and the identified data can then be used to craft better and more engaging ads that result in an increasing number of instals, revenue, and success.

The IDFA can be reset to any user on each iOS device by going to Security and Privacy settings. Users can simply switch off the “Allow Apps to Request to Track” option and then switch it on (if they wish to have it on) to reset it. Each time it is toggled off and on again, the IDFA resets.

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The depersonalisation of user data offers a certain level of data protection to users. However, it still allows advertisers and marketers to leverage device-specific data and perform targeted advertising.

The Android equivalent to IDFA is the Google Advertising ID (GAID), sometimes also referred to as the Android Advertising ID (AAID). Android users can also access and reset their GAID to opt out of personalisation in their Privacy settings.

IDFA After iOS 14.5

The ability to use IDFA was dramatically impacted in 2021 with Apple’s move towards user-enhanced privacy in correspondence to the App Tracking Transparency (ATT) framework. It limited the use of IDFA for mobile campaign measurements.

A marketer or advertiser needs to request permission to access the IDFA and track the user at the device ID when it’s running iOS 14.5 or later. If the user does not opt-in to allow the tracking, the only way a marketer can perform attribution for campaigns run on iOS is via Apple’s SKAdNework (SKAN).

SKAN is Apple’s API-based, privacy-centric framework that provides advertisers insight, helping in ad measurement. However, this cuts out third-party attribution vendors and is limited in its ability.

How Does the Limited Access to IDFA Impact Advertisers and Publishers?

The limitation of IDFA was implemented to change the mobile marketing ecosystem for Apple users, making it more privacy-centric. This has limited advertisers and marketers to assess the campaign measurement.

IDFAs also played a key role in detecting ad fraud. By monitoring the stream of ad actions and their associated IDFAs, marketers were able to get important insights that helped in flagging fraudulent activities.

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Therefore, reducing access to IDFAs as freely as before has significantly impacted advertisers to engage their audiences to create personalised experiences and measure the effectiveness of a campaign.

What Steps Can Advertisers Take with the Implementation of ATT?

In order to make the most of SKAdNework and an IDFA-less ecosystem, advertisers can take the following steps:

Data Aggregation: Advertisers can collect all SKAdNework information from each ad network.
Data Validation: They should make sure all postbacks are signed by Apple and aren’t manipulated in transit. A trusted mobile measurement partner (MMP) can help in managing this issue.
Data Enrichment: Match SKAN information with other relevant data points such as clicks, impressions, and organic traffic, for a complete ROI analysis.
Data Enablement: Ensure SKAdNework data is available for convenient consumption by using your MMP’s dedicated dashboards and APIs.
Seamless Integration: When your MMP solution provides a proper integration with SKAN, you do not need to put any effort from your end as it enables you to gear up towards future changes in the SKAdNework protocol.
Conversion Events: Measure server-side, dynamic and flexible in-app events for better conversions.


An IDFA helps marketers monitor user engagement with their ads by keeping track of their post-install activity. It allows advertisers to create targeted and personalised ad experiences.

With Apple’s ATT framework in the picture, the use of IDFA became significantly limited since advertisers can only track app data if users allow the opt-in. However, ATT opt-in rates are gradually increasing as users become aware of the benefits of targeted advertising and developers become better at communicating this value.

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