If you are running Meta ads and have never looked at your Event Match Quality score, you are likely paying more per conversion than you need to. EMQ is one of the most underrated levers in Meta advertising — and one of the easiest to improve once you understand what drives it.
This article covers what Event Match Quality is, which parameters move the needle, why the Meta Andromeda algorithm update made it more important than ever, and how the Conversions API can take a typical score of 4-6 up to 8-9.
What Is Meta Event Match Quality?
Event Match Quality (EMQ) is a score from 0 to 10 that Meta assigns to each conversion event source. It measures how effectively the customer information sent with your events can be matched to a Facebook or Instagram account in Meta's user graph.
When a visitor converts on your site, Meta needs to link that conversion event to a specific user profile — to update that person's ad delivery, attribute the conversion to the right campaign, and feed your Lookalike Audiences and campaign optimisation algorithms.
The better the match, the better all of those downstream processes work.
You can find your EMQ score in Meta Events Manager: select your pixel, click on a specific event (e.g. Lead or Purchase), and look for the Event Match Quality column.
Why EMQ Matters More Than Ever: The Meta Andromeda Update
In 2023, Meta rolled out the Andromeda algorithm — a fundamental rebuild of how Meta's ad delivery and optimisation engine works. The new system is significantly more reliant on conversion signal quality to decide who to show your ads to and how to bid.
Before Andromeda, Meta's algorithm could make reasonable optimisation decisions even with incomplete or low-quality signal. The system had enough behavioural data from platform engagement to fill in the gaps.
After Andromeda, conversion signal became the primary input. The algorithm gives far more weight to actual conversion events — and specifically to how well those events are matched to real user profiles.
A low EMQ score means:
- Your conversion events are being partially or fully attributed to the wrong users
- Your optimisation algorithms are training on corrupted data
- Lookalike Audiences built from your converters are less accurate
- Your cost per conversion rises because the system cannot find more people like your actual buyers
A high EMQ score means:
- Conversions are correctly attributed to real Meta users
- Your algorithms see a clean signal of what your actual buyers look like
- Lookalike and Advantage+ audiences improve in quality
- CPA drops, ROAS improves — without changing a single creative
Sending more conversion events with better matching parameters is now one of the most direct ways to improve campaign performance on Meta.
The Parameters That Drive Your EMQ Score
Meta calculates your EMQ based on the customer information you pass with each event. Not all parameters are equal — some contribute significantly more to the score than others.
Tier 1: Highest impact
Email address (em)
The single most important matching parameter. Meta's user graph is built around email addresses — it is how most accounts are created and verified. A hashed email match is the strongest signal available. Even one valid email address can push a match from weak to strong.
Phone number (ph)
The second strongest individual parameter. Many Meta users have verified phone numbers attached to their accounts. Hashed phone number combined with email produces the most reliable match available.
Tier 2: Strong supporting parameters
First name (fn) and last name (ln)
Used in combination with other parameters to disambiguate between users with the same email domain or phone prefix. On their own they are weak; combined with email or phone they strengthen the match significantly.
External ID (external_id)
A stable, unique identifier you assign to the user — typically from your CRM, your email platform, or your own database. If the same external ID appears in multiple events, Meta can link them into a coherent conversion journey even if other parameters are missing.
Click ID (fbc / fbclid)
The fbclid parameter appended to URLs when a user clicks a Meta ad. When captured correctly and passed with events, this creates a direct link between the ad click and the conversion — the strongest possible attribution signal. It does not depend on matching at all; it is a deterministic link.
Browser ID (fbp)
The _fbp cookie set by the Meta pixel on the user's browser. Used for session-level matching when other parameters are not available.
Tier 3: Server-only parameters (CAPI)
Client IP address (client_ip_address)
Only passable via the Conversions API — the browser pixel cannot reliably include this. Used for probabilistic matching when identity parameters are unavailable.
Client user agent (client_user_agent)
Similarly server-side only. Combined with IP address, it helps Meta distinguish between users accessing from the same network.
What a complete event looks like
An event with maximum EMQ includes:
em + ph + fn + ln + fbc + fbp + external_id + client_ip_address + client_user_agent
Meta's internal documentation suggests that hitting 7 or more matching parameters consistently, with accurate data, produces scores in the 8-9 range.
Why Browser-Only Tracking Gives You a Score of 4-6
A standard Meta pixel setup — without the Conversions API and without advanced matching — typically produces an EMQ score between 4 and 6. Here is why.
The pixel can only see what the browser shares. IP address and user agent are technically available in browser requests, but browsers increasingly obscure or anonymise them. Safari strips identifying headers. Privacy-focused browsers send generic user agents.
Cookie restrictions limit fbp reliability.
Safari ITP limits first-party cookie lifetimes to 7 days. If the _fbp cookie has expired by the time the conversion happens, that parameter is missing.
Ad blockers block the pixel entirely. On average, 30-40% of desktop users have ad blockers installed. For those users, the pixel never fires — and EMQ for those events is zero, because no event is sent at all.
GDPR consent banners reduce your matched population.
In the EU, if a visitor declines marketing cookies, the Meta pixel cannot initialise. No fbp, no fbc, no pixel event. For EU-heavy audiences, 20-35% of visitors are typically invisible to pixel tracking.
First-party identity data is often not passed. Unless you have explicitly configured advanced matching in Meta Events Manager, visitor email, phone, and name are not included in pixel events — even when the visitor has filled a form on your site.
The result: a pixel with default settings, for an EU B2B audience, with a typical ad blocker rate, might consistently produce EMQ scores of 4-5. Meta is matching your conversion events against a fraction of the actual converters.
How the Conversions API Pushes Your Score to 8-9
The Conversions API (CAPI) changes what data is available at event time. Because events are sent server-side, several categories of data that are unavailable or unreliable in the browser become fully accessible.
Server-side events include IP and user agent reliably. The CAPI request originates from your server — or in LeadSignal's case, from LeadSignal's infrastructure. The IP address of the user and their browser's user agent are captured at the time of the page request and included in the server-side payload, unaffected by browser privacy restrictions.
CAPI events reach Meta even when the pixel is blocked. For the 30-40% of users with ad blockers, server-side events are the only events that arrive at Meta at all. Without CAPI, these conversions have an EMQ of zero — they are completely invisible. With CAPI, they are matched as well as the available parameters allow.
First-party identity data flows with every event. When a visitor fills a form — submitting their email, phone number, first name, and last name — that data is captured server-side and hashed before being sent to Meta. This is the highest-impact change for EMQ: moving from no identity parameters to full identity parameters in a single step.
The fbclid click ID is captured on the server.
LeadSignal captures the fbclid URL parameter when the visitor first arrives from a Meta ad and stores it server-side. It is then included in all subsequent conversion events for that session — even if the browser cookie has expired or been blocked.
Combined effect on EMQ:
| Setup | Typical EMQ score | Parameters passed |
|---|---|---|
| Browser pixel, no advanced matching | 4-5 | fbp, partial fbc |
| Browser pixel with advanced matching | 5-7 | Adds em, ph, fn, ln (if form data available) |
| CAPI only, no identity data | 5-6 | client_ip, client_user_agent, fbc |
| Browser pixel + CAPI, full parameters | 8-9 | All parameters, complete identity matching |
The ceiling of 8-9 is realistic when CAPI is running alongside the pixel and identity parameters (email, phone, name) are consistently captured from form fills.
Reaching a 10 is rare and typically requires additional identifiers like Meta's Lead ID or Subscription ID, which apply to specific campaign types.
The Role of Consent: Why GDPR Compliance and High EMQ Are Not Opposites
A common misconception: "GDPR means I cannot pass customer data to Meta, so I cannot improve my EMQ."
The reality is more nuanced. GDPR regulates identity tracking without consent — it does not prohibit passing first-party data that a user has voluntarily provided, when you have the appropriate legal basis.
When a visitor fills your contact form and submits their email and phone number, that data is provided voluntarily. If your privacy policy covers use of that data for advertising purposes, and the user has given marketing consent, you can pass that data to Meta via CAPI — hashed, as Meta requires.
The key distinction:
- Without marketing consent: no
fbpcookie, no pixel initialisation, no identity tracking. CAPI can still send server-side events with IP and user agent only — partial signal, EMQ around 5-6. - With marketing consent: full signal. Email, phone, name, click IDs, cookies — all parameters available. EMQ 8-9.
This is why consent rate matters beyond just legal compliance. A well-designed consent banner that earns higher opt-in rates directly translates into higher EMQ scores and better campaign performance.
Improving Your EMQ With LeadSignal
Implementing CAPI with full matching parameters from scratch involves:
- Setting up server-side infrastructure
- Capturing and hashing identity data correctly (SHA-256 normalised, as Meta requires)
- Forwarding
fbclidandfbpfrom browser to server - Deduplicating browser and server events with matching
event_id - Keeping up with Meta's evolving parameter requirements
LeadSignal handles all of this automatically, without requiring any configuration beyond entering your Pixel ID and CAPI access token.
When a visitor fills a form on your site, LeadSignal:
- Captures email, phone, first name, and last name from the form fields using intelligent heuristics — no manual field mapping
- Hashes the data client-side before it ever leaves the browser
- Forwards the hashed parameters with every subsequent event in the session
- Captures
fbclidon the first page load and persists it for the session - Sends a server-side CAPI event with all available parameters in parallel with the browser pixel
- Includes a shared
event_idin both events so Meta deduplicates automatically
The result: every form fill on your site becomes a high-quality matched conversion event — EMQ 8-9, consistently, without writing a line of code.
What a Higher EMQ Score Means for Your Campaigns
The practical impact of moving from an EMQ of 4-5 to 8-9 compounds across every part of your Meta account.
Lookalike Audiences improve. Lookalikes are built from your matched converters. Better matching means a more accurate picture of who your real buyers are — and Lookalike Audiences built from that data find more of them.
Advantage+ campaigns perform better. Meta's Advantage+ Shopping and Advantage+ Audience campaigns are heavily dependent on conversion signal quality. Higher EMQ feeds a better training signal directly into these automated campaigns.
Attribution accuracy improves. View-through and click-through attributions are more reliably assigned to the correct campaigns. Your reporting reflects reality more closely — which means you can make better budget allocation decisions.
Retargeting audiences are more complete. Custom audiences built from website events include users whose pixel events were blocked but whose CAPI events were captured. Your retargeting pool is larger and more accurate.
Cost per result drops. This is the end result of all of the above. Better matched events produce better optimisation, which produces better ad delivery, which produces lower CPAs over time.
The EMQ score is a diagnostic metric — it tells you how much of this upside you are currently leaving on the table. Most advertisers running without CAPI and advanced matching are leaving a significant amount.