Technology

Aggregated Event Measurement (AEM)

Meta's privacy-focused measurement framework for iOS 14.5+ users who opt out of tracking via ATT.

Aggregated Event Measurement (AEM) is Meta's solution for measuring conversions from iOS users who block tracking via App Tracking Transparency. Limitations: Maximum 8 conversion events per domain (must prioritize which events to track), 24-48 hour delay in reporting (no real-time data), and data shown in aggregate only (no user-level detail). How to configure: In Meta Events Manager, rank your 8 most important events (e.g., Purchase, AddToCart, Lead). Meta will only report on these 8 for iOS opt-out users. Impact: Cannot optimize campaigns in real-time, limited conversion data, and must carefully choose which events to track. AEM is a significant downgrade from pre-iOS 14.5 tracking but better than nothing. Workaround: Implement CAPI to improve measurement for opted-out users.

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External Resources

Aggregated Event Measurement

Frequently Asked Questions

What is Aggregated Event Measurement (AEM)?

Aggregated Event Measurement (AEM) is Meta's privacy-focused protocol designed to measure web and app events from iOS 14.5+ users who have opted out of tracking via Apple's App Tracking Transparency (ATT) framework. It is a necessary response to Apple's privacy changes, which severely limited user-level data collection. AEM works by processing conversion events in an aggregated, anonymized manner to help advertisers understand campaign performance while respecting user privacy. Key limitations include a maximum of eight prioritized conversion events per domain and a reporting delay of 24 to 48 hours, which prevents real-time optimization. AEM is a foundational component for advertisers to maintain some level of conversion tracking on Meta platforms in a privacy-compliant world.

How do you implement and optimize Aggregated Event Measurement for better results?

To implement AEM, you must first verify your domain in Meta's Business Manager and then configure your eight most critical conversion events in Events Manager. These eight events must be ranked by priority, as Meta will only report on the highest-ranked event that occurs for a user. Optimization under AEM requires a shift in strategy due to the reporting delay and limited event count. Instead of real-time, granular optimization, focus on broader, long-term performance trends. Prioritize high-value, bottom-of-funnel events like 'Purchase' and 'Complete Registration' in your eight slots. For more accurate and timely data, AEM should be used in conjunction with the Conversions API (CAPI), which sends server-side data directly to Meta, helping to recover lost conversions and improve the Event Match Quality (EMQ) score.

What is the difference between Aggregated Event Measurement and the Conversions API (CAPI)?

Aggregated Event Measurement (AEM) and the Conversions API (CAPI) are both Meta tools for post-iOS 14.5 tracking, but they serve different functions. AEM is a **protocol** that governs how data is processed from iOS users who opt out of tracking, imposing limitations like the 8-event cap and reporting delays to comply with Apple's privacy rules. It is a forced framework for opted-out users. In contrast, the Conversions API (CAPI) is a **server-side connection** that sends web and app events directly from your server to Meta, bypassing browser-based tracking restrictions like ad blockers and cookie limitations. CAPI is a **method of data delivery** that improves the accuracy and reliability of all event data, including those subject to AEM. For the best measurement, advertisers should implement CAPI to deliver event data, which is then processed according to the AEM protocol for opted-out iOS users.

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