What is the Identifier for Advertisers: IDFA?

What is IDFA Used For?

Advertisers use IDFA data to measure ad performance, optimize campaigns, and perform data-driven user acquisition strategies.

When an ad network supports IDFA tracking and the advertiser records ad interactions, the IDFA can let you see which users clicked an ad. 

Users can turn off such tracking to manually reset or disable it, or turn on Limit Ad Tracking (LAT). Limit Ad Tracking is an iOS feature that allows users to opt out of sharing their data. 

When this setting is on, the user’s IDFA is hidden (shown as zeros), so ad networks can’t track the device or show personalized ads. 

The Android equivalent of IDFA is the Google Advertising ID (GAID). Users can also reset their GAID to opt out of personalization on their Android devices. 

IDFA Affected by iOS 14.5 & App Tracking Transparency (ATT)  

Back in 2021, Apple flipped the switch on how tracking works in mobile app advertising. 

With iOS 14.5, Apple introduced App Tracking Transparency (ATT), and apps could no longer access the IDFA automatically. 

Instead, users now get a pop-up: “Allow this app to track your activity?” With this update, advertisers lost the ability to follow users across apps unless they opted in.

Impact of ATT on IDFA Opt-in Rates

A recent Singular study shows ATT opt-in rates dropped from 26% in 2021 to under 14% in mid-2024. 

But there’s hopeful news for advertisers. Globally, 50% of users consent to tracking in 2025, a 10% increase since ATT’s initial rollout.

Games see higher opt-ins than other apps (about 19% vs. 12%), but results vary by category. Weather apps can reach 40%, while News and Medical are often below 5%. 

If the user does not consent to allow IDFA tracking, the only way to perform attribution for iOS campaigns is with Apple’s SKAdNetwork (SKAN) and/or AdAttributionKit.

One effective way to increase opt-in rates is through thoughtful onboarding. For example, adjoe’s Playtime ad format addresses the challenge by guiding users step by step. 

It clearly communicates the value exchange and reframes ‘tracking’ as ‘personalization.’ This level of transparency builds trust and has proven results, driving opt-in rates up to 70%, far above the industry average.    

IDFA Impact on Advertisers 

Without IDFA, advertisers lose much of the targeting precision they once had. 

Tracking ad performance and user behavior has become much harder. You cannot identify and retarget users individually, unless they opt in to IDFA. 

Advertisers struggle to measure LTV, ROI, and user actions with limited detail and accuracy in SKAdNetwork (SKAN). Conversion tracking can be delayed (at least 24 hours after install), making campaign optimization harder.

SKAdNetwork’s limitations have led to a rise in ad fraud due to fewer anti-fraud signals and reduced transparency.

Future of App Advertising in the Post-IDFA World 

SKAdNetwork (and Apple’s new AdAttributionKit) dominate privacy‑safe attribution, offering aggregated, anonymous campaign insights via postbacks rather than device IDs.

There’s a shift towards AI‑powered contextual advertising, first-party data, and server-side measurement. 

App marketers are increasingly using incrementality testing, media mix modeling, and engagement-based attribution (e.g., session length, retention rate). It helps evaluate campaign performance without relying on granular tracking.

MMPs originally relied on IDFA for device-level attribution. But now they enable privacy-first measurement by aggregating SKAdNetwork postbacks from Apple and ad networks. 

They are also applying probabilistic models when deterministic data is unavailable.

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