There is a number buried three clicks deep in Meta's Events Manager. It looks like a school grade, scored out of 10. Plenty of advertisers have never opened the page it lives on.
It can matter more to your return on ad spend than your last four creative tests combined.
It is called Event Match Quality, and if yours is low you are paying a tax on every conversion you buy. In plain terms, it scores how well Meta can connect each sale or lead you report to a real account. Better matching means the algorithm learns from accurate data and finds more buyers like your real ones.
Below is what the score measures, why it matters more than it used to, and how to fix it in an afternoon.
What the score is telling you
When someone buys from you, your website tells Meta a conversion happened. Meta then has to work out which of its billions of accounts that conversion belongs to.
It does that by comparing the customer information you send (email, phone, name, location, browser identifiers) with its own records. Meta's documentation says the score reflects which of those details you send, how good they are, and what percentage of your events end up matched to an account.
A high score means Meta can tie most of your conversions to the people who made them, and so to the ads they saw. A low score means it received a conversion notification and often could not attach it to a human.
Now think about what that does to an optimisation system. It learns by studying the people who converted and finding more like them. With bad matching, it is studying a blurred, partial sample.
Your creative decides who stops scrolling. Your match quality decides whether the machine ever learns why.
Why this got urgent
Two changes turned a technical nicety into a primary lever.
First, browser tracking kept getting more restricted. Safari has capped script-set cookies at seven days since 2019, identifiers get stripped, and a share of conversions never make it back through the browser at all. What used to be automatic now has to be sent deliberately from your server.
Second, ad delivery leans harder on prediction. The system is forecasting who is likely to convert before it shows an ad, and a forecast is only as good as its training data. Your conversion signal is the training data.
So the platforms got better at using signal just as signal got harder to collect. Advertisers who solve the collection problem give the system more to work with. The ones who don't tend to conclude the platform has stopped working.
This ties directly into how Meta now picks who sees your ads. With detailed targeting doing less of the work, the algorithm leans on your creative and your conversion data to find buyers. We cover the targeting side in why broad targeting wins and the delivery side in what Meta's Andromeda update changed. Both assume the system is being fed clean signal.
How to find your score in five minutes
- Open Events Manager and select the dataset (pixel) connected to your website.
- Find your key events in the overview: purchase, lead, complete registration, whichever one your campaigns optimise for.
- Click into that event and open the Event Match Quality detail. You'll see the score and which customer parameters are being received.
- Note which parameters are missing and what share of events include each one. That is your to-do list.
- Repeat for every event you optimise toward. Scores can differ a lot between events on the same site.
If you see no score at all, you're probably not sending server events yet. That's step one of the fix.
The fix, in order of impact
One. Run the Conversions API alongside the pixel. Keep both. The pixel reports from the browser and the API reports from your server. Meta recommends exactly this pairing and calls it a redundant setup. Server reporting keeps working when a blocker or a failed page load kills the browser event.
On mainstream website and ecommerce platforms this is usually a native integration or an app install, with no development project needed.
Two. Send more customer parameters. Meta's own best practice guide names email address, IP address, name and phone number as the details that lift the score. City, state, postcode and country can go along too. Contact details are hashed first, which the integration handles for you.
The quickest wins usually come from sending information you already have. If a customer buys with an email address and your integration only sends browser identifiers, you are withholding the one field most likely to match them.
Don't forget the identifier that comes from the ad click itself. Meta's click ID is stored in a cookie on your domain called _fbc. If your site passes it back with the conversion, Meta has one more thing to match on. Many integrations handle this, but custom checkouts and multi-step forms often drop it along the way.
Three. Fix deduplication. Meta treats a pixel event and a server event as the same conversion only when the event name and event ID are identical and both arrive within 48 hours. Get that wrong and every sale is counted twice.
Four. Clean the data at the source. Phone numbers stored in five different formats, email fields with stray spaces, test orders nobody excluded. Rubbish in, low score out.
What good looks like
Meta's developer documentation gives no pass mark. Our rule of thumb: aim for above 7 on your primary conversion event, treat above 8 as strong, and treat anything below 6 as a sign Meta is struggling to match your conversions to real people.
Check the score per event. You can see a healthy score on page views and a poor one on purchases, which is backwards, because the purchase event is the one that trains delivery.
And check it after every website change. Match quality can slip when a form gets rebuilt, a checkout gets updated or a plugin gets replaced. Put a monthly look in the diary.
A worked example: the lead-gen business flying blind
Here's a hypothetical. Say you run a solar installation company in Perth, spending $6,000 a month on Meta lead campaigns. Your form sits on your website and collects name, email, phone and postcode. The pixel fires a lead event when the thank-you page loads. Nobody has ever opened Events Manager.
When you do, the lead event scores a 4. The reason is simple. The pixel only sends browser identifiers. Your form collects the very fields Meta needs to match people, and none of them are being passed through. On top of that, a chunk of visitors use browsers that block the pixel, so some leads never get reported at all.
The fix takes an afternoon. You connect the Conversions API through your website platform's integration and pass the hashed email, phone, first name and postcode with each lead event. The click ID gets stored and sent back. A shared event ID lets pixel and server events deduplicate, and your test leads get excluded.
A week later, the score has climbed. The campaigns and the creative are untouched. But the algorithm now knows which people filled in the form, and it can look for more of them. Watch three things next: cost per lead, lead quality as your sales team reports it, and whether your creative test results start to look more consistent.
The uncomfortable comparison
Think about where your last ten hours of marketing effort went. Probably creative. Maybe audience testing. Possibly a debate about a headline.
An account with poor match quality is running every one of those tests on patchy data. The winner you crowned might have won because its conversions happened to be easier to match, and the better ad lost.
So the cost goes past weaker delivery. Your testing programme produces conclusions you cannot trust, and those conclusions guide the next quarter of decisions.
Creative still matters enormously. We'd argue most ROAS problems are creative problems. But you can't diagnose a creative problem when the scoreboard is broken. Fix the measurement, then judge the ads.
The privacy question, answered plainly
Owners often hesitate here, and the hesitation deserves a straight answer.
Contact details such as email and phone number must be hashed before they are sent through the Conversions API. Meta says its systems are designed not to accept them unhashed, so it matches hashes against hashes. Technical identifiers such as IP address, user agent and click ID are sent unhashed.
You still have obligations. Tell people in your privacy policy what you share and why, honour opt outs properly, and do not send data for people who asked you not to.
Skipping the whole thing does not make you more compliant. It only makes your advertising more expensive.
This is part of a bigger shift. Businesses that collect and respect their own customer data are in a stronger position on every platform, which is why we argue you should own your audience instead of renting it.
Do this today
Open Events Manager. Find your primary conversion event. Read the score.
If it is under 7, we'd put it ahead of the creative, the budget and the new platform someone suggested on this month's list.
Fix it and the same ads on the same budget get a fairer chance, because the system can finally see who is buying from you.
It is the least glamorous work in advertising, and some of the cheapest. If you'd rather not wrestle with Events Manager yourself, our advertising team audits the setup, connects the Conversions API properly and keeps an eye on the score as your site changes.
Frequently asked questions
What is a good Event Match Quality score on Meta?
The score runs out of 10 and Meta's developer documentation does not set a pass mark. As a working rule, aim for above 7 on the conversion event your campaigns optimise for and treat above 8 as strong. Below 6 suggests Meta is struggling to connect your conversions to real people. Check each event individually, because a healthy page view score can hide a weak purchase or lead score.
Do I need the Conversions API if I already have the Meta pixel?
Yes, for most advertisers. The pixel reports from the browser, which is increasingly blocked or restricted. The Conversions API reports from your server, so it can report events the pixel loses. Meta recommends running both, with matching event names and event IDs so it can deduplicate them. Many website and ecommerce platforms offer this as a built-in integration.
How do I improve Event Match Quality quickly?
Send more customer parameters with each conversion, especially hashed email and phone, which your forms or checkout usually already collect. Add name, city, postcode and country where available. Pass the ad click ID back with conversions, fix deduplication with consistent event IDs, and clean up messy data such as inconsistent phone formats and test orders. Recheck the score about a week later.
Is sending customer data to Meta allowed under privacy law?
Contact details such as email and phone number must be hashed before they are sent through the Conversions API, so Meta receives scrambled values, not readable emails or phone numbers. You still need to disclose this sharing in your privacy policy, honour opt-outs and avoid sending data for people who have asked you not to. If you are unsure about your specific obligations, get advice relevant to your jurisdiction.