What is Event Match Quality?
Event Match Quality (EMQ) is a score from 0 to 10 that Meta assigns to every conversion event you send via the Conversions API. Google and TikTok have similar scores. The score indicates how well the platform can match the event to a real user.
A high EMQ (8+) means the platform knows who the event belongs to, can credit the campaign, and can train the algorithm. A low EMQ (below 6) means the opposite.
Why EMQ matters for ROAS
Meta uses machine learning to decide who sees your ads. That model trains on your conversion data. If 40% of that data is missing or low quality, the model trains on a broken picture. The result is higher CPMs, lower conversion rates, and an algorithm that never leaves learning.
Why your EMQ is probably low
- Ad blockers. 30 to 40% of desktop users block tracking pixels.
- iOS privacy updates. Since iOS 14.5 the Meta Pixel captures less.
- Missing identifiers. Many stores send events without email, phone, or other match keys.
What counts toward a high EMQ
- Hashed email, weighted heaviest, +2.5.
- _fbp cookie, +1.5.
- _fbc click ID, +1.5.
- Hashed phone, +2.0.
- IP plus user agent, +1.0 together.
- Name, address, zip, +0.1 to +0.2 each.
Most Shopify stores only send _fbp and IP via the client-side pixel. That lands around 5.0 to 5.5 EMQ. With server-side CAPI and advanced matching you reach 8.0 to 9.5.
How you improve EMQ
- Implement server-side CAPI. Ad blockers cannot block server-to-server traffic.
- Enable advanced matching. Send hashed email, phone, name, and address with every purchase.
- Use identity stitching. Link anonymous sessions to known customers as soon as they enter an email.
Among Layer Insights customers, average EMQ improves by +2.8 points within 48 hours of activation. Most go from about 5.2 to 8.0+. That is better optimization, lower CPMs, and more conversions from the same budget.