Event Match Quality (EMQ) is one of the most important diagnostics in Meta’s tracking ecosystem, yet many advertisers don’t fully understand how it works. EMQ measures the accuracy, completeness, and consistency of the user identifiers you send through Pixel and CAPI. A high EMQ score helps Meta match more events to real users, optimize faster, improve attribution, and ultimately lower your CPA. This guide explains what Event Match Quality is, why it matters, how Meta calculates the score, and the most effective ways to improve EMQ in 2025.

What Is Event Match Quality (EMQ)?

Before improving EMQ, it’s important to understand what the score actually measures—and what it does not measure. Event Match Quality is Meta’s assessment of how effectively your events are matched to real users across Meta platforms.

In simple terms:

Event Match Quality = The quality, completeness, and accuracy of user identifiers you send with each event.

How EMQ Appears Inside Events Manager

You can view EMQ inside:

Meta Events Manager → Your Pixel or CAPI → Diagnostics or Overview

Here, Meta displays:

• A score from Poor → Okay → Great
  

• A breakdown of the identifiers detected
  

• A list of missing, incomplete, or low-quality identifiers
  

• Browser vs Server match quality
  

• Recommended improvements

Why EMQ Directly Impacts Ad Performance

A strong EMQ score is more than a nice diagnostic—it directly influences your advertising efficiency. When Meta’s machine-learning system receives high-quality, well-matched data, it optimizes faster and more accurately.

Here’s how:

1. Better Training Signals for Optimization

Meta’s delivery system depends on conversion signals to predict which users are most likely to take action. When EMQ is high:

• More events are successfully attributed
  

• Modeled conversions become more accurate
  

• Lookalike audiences improve
  

• Retargeting lists become more complete
  

A poor EMQ means your events are essentially “floating”—Meta can’t confidently tie them to a user.

2. Faster Learning Phase Exit

The learning phase requires enough high-quality signals.
With weak EMQ, events drop off, and campaigns stay in learning longer, causing unstable CPAs.

3. Higher Reliability After iOS + Browser Restrictions

Modern tracking is fragmented. Server-side tracking (CAPI) and stronger identifiers help fill the gaps.

4. Better Attribution Accuracy

If events are matched properly, Meta can reliably attribute conversions, reducing the “black box” effect that advertisers often complain about.

What Influences Event Match Quality Scores?

If your EMQ score is low, it's not a mystery. It's a composite score based on a few key technical factors.

Understanding these factors is the first step to diagnosing your own setup.

The Quality and Quantity of Customer Information

This is the single most important factor. The score is heavily weighted by which identifiers you send.

• Top-Tier: Hashed Email (em), Hashed Phone (ph), External ID (external_id). These are unique, persistent, and high-confidence identifiers.

• Mid-Tier: fbp (Browser Cookie), fbc (Click ID). These are excellent for matching but can be lost due to browser settings or ad blockers.

• Low-Tier: IP Address (client_ip_address), User Agent (client_user_agent). These are used as supporting signals but are not very precise on their own.

A Purchase event sent with only an IP address and User Agent will have a Poor EMQ. A Purchase event sent with a hashed email, hashed phone, fbp, and fbc will have a Great EMQ.

The Timing and Deduplication of Events

In a modern setup, you send events from both the Meta Pixel (browser-side) and the Conversions API (server-side). This is called a "hybrid" setup, and it's essential for success.

• Meta Pixel sends browser-level data (like fbp, fbc).

• CAPI sends rich, reliable PII (like hashed email, phone) from your server.

Meta needs to know that the Purchase event from the Pixel and the Purchase event from Meta CAPI are the same event. This is called deduplication. If you fail to deduplicate, Meta may double-count your events or get confused, which hurts EMQ.

The Consistency of Data Across Pixel and CAPI

Deduplication relies on a unique event_id. You must generate this event_id in the user's browser, send it with the Pixel event, and also pass that exact same event_id to your server to be sent with the CAPI event.

If the event_id is missing or mismatched, deduplication fails, and your EMQ score will suffer.

How Meta Calculates Event Match Quality

Let's pull back the curtain on how Meta's system actually generates your score from 0 to 10.

The calculation is primarily based on two things:

1. Match Key Quality: A score is assigned to each event based on which parameters you sent. Sending a hashed email is worth more points than sending a user agent.

2. Event-Level Match Rate: Of all the events you sent in the last 7 days, what percentage of them did Meta actually match to a user account?

Meta's documentation explains that the final score is a weighted average. This is why you can have a "Great" score (e.g., 9.0) even if you don't have a 100% match rate. The system understands that you won't be able to provide PII for every anonymous PageView.

How to Improve Facebook Event Match Quality

Improving Event Match Quality requires a combination of cleaner data, more identifiers, consistent formatting, and correct implementation across Pixel, CAPI, and CRM systems. Before moving into advanced tactics, let’s strengthen the fundamentals—these are the core optimizations Meta expects advertisers to follow.

1. Send More Customer Information Parameters (CAPI + Pixel)

Meta explicitly states in its documentation that “the more customer information parameters you send, the higher the chance your events can be matched to a user.” This means your implementation should always send:

• Email
  

• Phone number
  

• First & last name
  

• ZIP / City / State
  

• Country
  

• External ID (powerful unique identifier)
  

• fbp / fbc browser IDs
  

• Client IP + User Agent
  

• Click ID (fbclid)
  

And every piece of data must be hashed using SHA-256 before transmission.

Why this increases EMQ

Because more signals = more match opportunities.
If the Pixel sends only browser-level identifiers, Meta may score your event Signal Quality lower than 6/10. Adding hashed email + phone can increase the score to 8–9/10, depending on data cleanliness.

2. Fix Inconsistent Formatting Across Systems

One of the biggest causes of low EMQ is dirty data. This includes cases where:

• Names contain extra spaces
  

• Phone numbers use different international formats
  

• Emails contain uppercase letters or typos
  

• Country codes are missing
  

• ZIP codes are inconsistent (e.g., “10001-2345” instead of “10001”)
  

Best practice is to normalize data before hashing:

• Lowercase emails
  

• Remove punctuation in phone numbers
  

• Trim whitespace in names
  

• Use ISO country codes
  

• Standardize ZIP to 5 or 6 digits depending on the country.
  

3. Implement CAPI Properly (Not Just Browser Pixel)

Since iOS 14 and tracking limitations, relying on the browser pixel alone reduces match rates. Server-side events (CAPI) improve EMQ because:

• They send backend customer data (like user account fields)
  

• They bypass browser blocking
  

• They pass precise identifiers captured during login or checkout
  

• They reduce loss caused by ad-blockers
  

Key requirement: Events must be deduplicated using event_id; otherwise Meta will treat Pixel + CAPI as separate events → lowering match rate.

4. Ensure High Data Freshness and Accuracy

Meta prioritizes recent, verified identifiers. You should:

• Collect updated emails during login or checkout
  

• Avoid prefilled outdated CRM entries
  

• Use phone verification when possible
  

• Sync CRM → CAPI regularly (daily ideally)
  

Old or inaccurate emails significantly lower EMQ because Meta cannot match them.

5. Improve Consent Collection for Tracking (Especially EU/UK)

If a significant percentage of website visitors opt out of tracking, EMQ drops automatically.

Solutions:

• Use cookie banners that encourage opt-in
  

• Explain value clearly (“Helps us show relevant offers”)
  

• Trigger server-side tracking for logged-in users even if browser cookies are limited.
  

6. Validate Events with Meta’s “Test Events” and “Diagnostics” Tools

Many advertisers think they implemented everything correctly — but Meta Diagnostics often shows:

• Missing customer information
  

• Hashing errors
  

• Incorrect parameter names
  

• Invalid event_ids
  

• Too many duplicate events
  

Fixing these technical issues can increase EMQ by 20–40%.

7. Match Events to the Correct Domain (Aggregated Event Measurement)

Misconfigured domains or mismatched pixels lower the quality score.
Double-check that:

• The domain is verified
  

• The pixel is correctly assigned
  

• Events are mapped under AEM with the right priority
  

When the wrong domain fires events, Meta almost always scores EMQ below 5/10.

How to Improve Facebook Event Match Quality

Improving Event Match Quality requires a combination of cleaner data, more identifiers, consistent formatting, and correct implementation across Pixel, CAPI, and CRM systems. Before moving into advanced tactics, let’s strengthen the fundamentals—these are the core optimizations Meta expects advertisers to follow.

1. Send More Customer Information Parameters (CAPI + Pixel)

Meta explicitly states in its documentation that “the more customer information parameters you send, the higher the chance your events can be matched to a user.” This means your implementation should always send:

• Email
  

• Phone number
  

• First & last name
  

• ZIP / City / State
  

• Country
  

• External ID (powerful unique identifier)
  

• fbp / fbc browser IDs
  

• Client IP + User Agent
  

• Click ID (fbclid)

Why this increases EMQ

Because more signals = more match opportunities.
If the Pixel sends only browser-level identifiers, Meta may score your event Signal Quality lower than 6/10. Adding hashed email + phone can increase the score to 8–9/10 depending on data cleanliness.

2. Fix Inconsistent Formatting Across Systems

One of the biggest causes of low EMQ is dirty data. This includes cases where:

• Names contain extra spaces
  

• Phone numbers use different international formats
  

• Emails contain uppercase letters or typos
  

• Country codes are missing
  

• ZIP codes are inconsistent (e.g., “10001-2345” instead of “10001”)
  

Best practice is to normalize data before hashing:

• Lowercase emails
  

• Remove punctuation in phone numbers
  

• Trim whitespace in names
  

• Use ISO country codes
  

• Standardize ZIP to 5 or 6 digits depending on country
  

3. Implement CAPI Properly (Not Just Browser Pixel)

Since iOS 14 and tracking limitations, relying on the browser pixel alone reduces match rates. Server-side events (CAPI) improve EMQ because:

• They send backend customer data (like user account fields)
  

• They bypass browser blocking
  

• They pass precise identifiers captured during login or checkout
  

• They reduce loss caused by ad-blockers
  

Key requirement: Events must be deduplicated using event_id; otherwise Meta will treat Pixel + CAPI as separate events → lowering match rate.

4. Ensure High Data Freshness and Accuracy

Meta prioritizes recent, verified identifiers. You should:

• Collect updated emails during login or checkout
  

• Avoid prefilled outdated CRM entries
  

• Use phone verification when possible
  

• Sync CRM → CAPI regularly (daily ideally)
  

Old or inaccurate emails significantly lower EMQ because Meta cannot match them.

5. Improve Consent Collection for Tracking (Especially EU/UK)

If a significant percentage of website visitors opt out of tracking, EMQ drops automatically.

Solutions:

• Use cookie banners that encourage opt-in
  

• Explain value clearly (“Helps us show relevant offers”)
  

• Trigger server-side tracking for logged-in users even if browser cookies are limited.
  

6. Validate Events with Meta’s “Test Events” and “Diagnostics” Tools

Many advertisers think they implemented everything correctly — but Meta Diagnostics often shows:

• Missing customer information
  

• Hashing errors
  

• Incorrect parameter names
  

• Invalid event_ids
  

• Too many duplicate events
  

Fixing these technical issues can increase EMQ by 20–40%.

7. Match Events to the Correct Domain (Aggregated Event Measurement)

Misconfigured domains or mismatched pixels lower the quality score.
Double-check that:

• The domain is verified
  

• The pixel is correctly assigned
  

• Events are mapped under AEM with the right priority
  

When the wrong domain fires events, Meta almost always scores EMQ below 5/10.

Common Reasons for Low Event Match Quality

If your score is "OK" or "Poor," it's almost always due to one of these common, fixable issues.

Missing or Incorrectly Formatted PII

This is the #1 culprit.

• Not Captured: Your server simply isn't capturing the user's email, phone, or name at checkout (or they're not logged in).

• Not Passed: Your server has the data, but your CAPI integration isn't configured to send it.

• Incorrect Hashing: This is a subtle but critical error. PII must be SHA-256 hashed. But before hashing, it must be normalized:

• Email: Trim whitespace and convert to lowercase. " John.Doe@Example.com " -> john.doe@example.com -> then hash.

• Phone: Remove all symbols, non-numeric characters, and include the country code. +1 (555) 123-4567 -> 15551234567 -> then hash.

• Name: Trim whitespace and convert to lowercase.

If you hash John.Doe@Example.com and Meta's system has john.doe@example.com on file, it will not match.

Poor or Non-Existent Event Deduplication

You have the Pixel firing. You have CAPI firing. But you never set up a unique event_id to link them.

In this case, Meta sees two purchase events for every one sale. It can't combine the Pixel's fbp/fbc data with CAPI's hashed email data. Your EMQ plummets because neither event has the full set of identifiers.

Missing Key Browser Parameters (fbp, fbc)

This happens if you make the mistake of using only CAPI. A CAPI-only setup cannot generate the fbp (browser cookie) or read the fbc (click ID from the URL).

Losing these two parameters is devastating for EMQ. You must use a hybrid setup (Pixel + CAPI) to get the best of both worlds.

Significant Data Transmission Delays

CAPI events should be sent as close to real-time as possible. If you batch and send your conversion events 24 hours later, the supplementary data (like IP address) is stale, and the event may fall outside the attribution window, hurting match rates.

FAQs About Event Match Quality

We've covered a lot. Here are some quick answers to the most common questions advertisers have.

What's a "good" EMQ score?

Aim for "Great" (8.0+), especially for your primary optimization event (e.g., Purchase). "Good" (6.0-7.9) is acceptable, but you're leaving money on the table. "OK" (4.0-5.9) is actively hurting your performance and needs to be fixed immediately. "Poor" (<4.0) is a critical error.

Why is my EMQ score different for ViewContent vs. Purchase?

This is normal and expected. You have far more customer data for a Purchase event (email, name, phone) than for an anonymous ViewContent event. Focus on maximizing the EMQ for your key, bottom-of-funnel events like InitiateCheckout, AddPaymentInfo, and Purchase.

Will improving EMQ fix my ad performance overnight?

No. It fixes the data overnight, but the algorithm needs time (a few days to a week) to re-learn using this new, high-quality data. You should see performance stabilize, your CPA trend downwards, and your attributed ROAS increase after the system exits the learning phase.

CAPI vs. Pixel - which one is better for EMQ?

This is the wrong way to think about it. They are a team. You must use both in a hybrid setup for the best possible EMQ.

• The Pixel is best at sending browser-specific data (fbp, fbc).

• The Conversions API (CAPI) is best at sending reliable, rich, private PII (hashed email, phone, external_id).

A high-EMQ setup combines the signals from both, linked by a single event_id.

Further reading:

• Meta Event Deduplication
• Meta Event Setup Tool