What is Event Match Quality and why is your Shopify store missing 40% of conversions?

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 in their system.

A high EMQ score (8+) means the platform knows exactly who this conversion event belongs to, can credit the ad campaign correctly, and can optimize the algorithm better. A low EMQ score (below 6) means the opposite.

Why does EMQ matter for your ROAS?

Ad platforms like Meta use machine learning to decide who to show your ads to. This algorithm is trained on your conversion data. If 40% of that data is missing or low quality, the algorithm trains on incomplete information.

The result: higher CPMs, lower conversion rates, and an algorithm that never exits the learning phase. Many Shopify stores spend thousands per month on ads without knowing the algorithm is working with only 60% of the actual data.

Why is your EMQ probably low?

There are three main causes:

• Ad blockers — 30-40% of desktop users have an ad blocker that also blocks tracking pixels
• iOS privacy updates — Since iOS 14.5, third-party cookies are blocked, so the Meta Pixel captures less data
• Missing identifiers — Many stores send events without email, phone, or other identifiers needed for matching

What counts toward a high EMQ score?

Meta weighs different identifiers. The most valuable:

• Email (hashed) — weighted heaviest, +2.5 points
• _fbp cookie — Meta's own browser cookie, +1.5 points
• _fbc cookie — Click ID from Meta ads, +1.5 points
• Phone number (hashed) — +2.0 points
• IP address + user agent — together +1.0 point
• Name, address, zip — each +0.1 to +0.2 points

Most Shopify stores only send the _fbp cookie and IP address via the client-side pixel. That gives an EMQ of about 5.0-5.5. With server-side CAPI and advanced matching you reach 8.0-9.5.

How do you improve your EMQ?

The approach consists of three steps:

1. Implement server-side CAPI — Send events from your server to Meta, separate from the browser. Ad blockers cannot block server-to-server traffic.
2. Enable advanced matching — Send hashed email, phone, name and address with every purchase event. SHA-256 hashing keeps the data GDPR-compliant.
3. Identity stitching — Link anonymous sessions to known customers as soon as they enter their email. This retroactively enriches all earlier events from that visitor.

How fast do you see results?

Among Layer Insights customers we see an average EMQ improvement of +2.8 points within 48 hours of activation. Most customers go from an EMQ of 5.2 to 8.0+. This translates to better algorithm optimization, lower CPMs, and more conversions from the same ad budget.

Conclusion

Event Match Quality is one of the most impactful yet least known metrics for Shopify stores running ads. A 3-point EMQ improvement can be the difference between a profitable and unprofitable ad campaign. Server-side CAPI with advanced matching is the only reliable way to consistently achieve high EMQ scores.