Aggregated Event Measurement
Also called AEM.
Meta's framework for measuring web events from users who opted out of tracking on iOS, which limits each domain to a prioritised set of conversion events.
Why it matters
It forces a ranking decision most advertisers make once and never revisit: which events matter most, given only a limited number can be measured for that traffic.
What goes wrong
The prioritisation is usually set when the pixel is first configured, by whoever was doing the setup, and then inherited for years. If your funnel has changed since, the events being measured may not be the ones you now optimise toward.
Next to this
- Conversions APIMetaMeta's server-to-server route for sending events, used alongside or instead of the browser pixel.
- Event Match QualityMetaMeta's score, from 1 to 10, for how well the customer information attached to your events lets Meta resolve them to a person.
- Signal lossThe umbrella term for measurement getting harder: third-party cookie restrictions, shortened browser storage lifetimes, consent refusals, and platform privacy changes, all reducing the share of activity that can be observed and attributed.
The rest of this step
Measure this on your own data
The diagnostic reads a CRM export in your browser and reports your volume, your match rate and the spread between your leads against the thresholds in this glossary. Nothing is uploaded and no account is needed.