Match quality & EMQ

A conversion the platform cannot attribute to a person is a conversion it cannot learn from. Match quality is the platform’s own measure of how likely the identifiers on your event are to resolve to one of its users.

Event Match Quality

Event Match Quality, or EMQ, is Meta’s metric. Meta defines it as an indication of “how effective the customer information parameters sent with your server event may be at matching events to Meta accounts”. It runs from 0 to 10, and Meta recalculates it continuously from the last 48 hours of data.

Meta states that a high EMQ “can help decrease your cost per action”, and that you cannot use unmatched events for attribution or ad delivery optimization.

It covers web events only

Meta calculates EMQ for website events sent through the Conversions API. It is not available for offline events, app events or conversion leads.

Offline conversions have their own measure, the offline data quality score. It is also out of 10 but is built from freshness, frequency, attribution and accuracy over the last 28 days rather than the last 48 hours. Meta does publish bands for that one: 8 to 10 is high, 4 to 7 is medium, and 0 to 3 is low. Uploading daily, and at least 12 times in any 14 day period, is what keeps freshness and frequency up.

What raises the score

Meta publishes a priority ranking rather than numeric weights. Email address and the Meta click ID are the only two it ranks as high.

Priority	Parameters
High	Email address, and the Meta click ID.
Medium	Phone number, country, date of birth, external ID, browser ID, and Facebook login ID.
Low	First name, last name, city, postcode, and lead.

Value, currency and the product fields describe the conversion rather than the person, and do not affect the score. The IP address and user agent are not in the ranking either, though Meta requires the user agent on web events and says sending both may help matching.

The practical rule is simple. Send every identifier you legitimately hold, on every event. Each additional identifier is another chance to match, and the cost of including one is nothing.

Where the Gateway helps

The Conversions API Gateway improves matching in four ways: it sends additional customer identifiers, it uses first party data to reduce the impact of browser restrictions, it enables Advanced Matching, and it makes collection consistent across sessions.

Reading EMQ in Signals

After Conversions API Gateway setup is complete, the Signal count icon opens the Gateway reporting view. It includes:

EMQ Score, the headline Event Match Quality figure.
EMQ Table, showing the score per event type, the parameter coverage percentage, and a trend indicator of improving, stable or declining, with a graph for the selected range.

The figures refresh on a daily pull from Meta. Datahash also calculates its own coverage based scoring from the identifiers actually present on your events, so you can see which parameters are missing rather than only the resulting score.

Datahash’s own guidance is to pay attention to events with low EMQ scores, since those are the ones limiting advertising effectiveness.

Other platforms

Each platform reports match quality in its own way and under its own name. The underlying advice does not change: more identifiers, correctly normalized, match better everywhere.

Diagnosing a low score

Symptom	Usual cause
Score low across all events	Too few identifiers mapped. Check Field Mapping.
Score low on one event type only	That event fires somewhere the identifiers are not yet known, for example a page view before sign in.
Phone coverage high but score still low	Phone numbers are missing their country code.
Score dropped suddenly	A source schema change. A renamed column stops being recognized and its values stop arriving.