Event Match Quality: What the Score Means and How to Improve It

Meta and CAPI · 4 min read · by Anna Viggeborn

Event Match Quality is Meta's estimate of how well the customer information you send with an event lets it match that event to a person. It is not a measure of whether the event fired. It is a measure of how usable the event is.

What moves the score

• Hashed email and phone number, the two strongest parameters.
• First and last name, city, state, postal code, country.
• External ID, a stable customer or session identifier you control.
• Click ID (fbc) and browser ID (fbp) passed through to server events.
• IP address and user agent on server side events.

Why the score suddenly falls

• A checkout change stopped passing email or phone to the server event.
• Hashing changed, for example values are no longer lowercased and trimmed before hashing.
• A consent update removed parameters for part of your traffic.
• fbc and fbp are no longer captured and forwarded.

What it means for decisions

A falling score usually shows up as falling attributed conversions and falling reported ROAS, while orders in your own system stay flat. Compare the two before touching budgets.