Facebook Event Match Quality – What it is and how to increase it

May 14, 2024
Aug 16, 2021
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Using Facebook conversion API, you can send events from your server to the Facebook server. Server-side tracking with configured custom subdomain helps to bypass ad blockers, ITPs, and iOS 14/15 restrictions. 

Together with Facebook Conversion API events, you should send additional parameters.

These parameters can be divided into three parts: 

The latter helps Facebook Conversion API match events you send from the server to real users. It can be any information like email or last name. These parameters were created to help Facebook identify users.

For every server event you send, FB will show you an event match quality score. This match quality score depends on the number of customer information parameters you send and their accuracy.

Facebook CAPI event match quality can significantly impact your campaign’s results and audience accuracy. Let me walk you through some tips on how to increase the Facebook match quality score in this blog post.

What is the Facebook event match quality score?Copy link to this section

The key to proper FB conversion API setup is the event match quality score. Why? Well, Facebook utilizes user data sent from your server to match event instances like adding a product to a cart to a specific FB account. In other words, events match quality grades the customer information you share. The number of the parameters sent affects the percentage of sent events. 

Facebook event match quality

User data can be divided into the following subcategories: 

    1) Parameters that require hash and can be sent as is.

Such parameters as zip code, email, or state need to be hashed (basically, all parameters that contain personal user information). But parameters like client user agent, IP address, or browser ID do not require a hash. 

    2) _fbp

Facebook pixel automatically ads _fbp cookie when it is using first-party cookies. This unique identifier consists of version (always FB), subdomain index (for example, 0 for, 1 for, etc.), creationTime in the UNIX time standard, and it represents time in milliseconds when _fbp cookie was saved and a random number. 

Here is the example: fb.1.1596403881668.1116446470

When the Facebook pixel is installed on a website and uses first-party cookies, the pixel automatically saves a unique identifier to an _fbp cookie for the website domain if one does not already exist.

    3) _fbc

When a user clicks on the FB ad, it includes the fbclid query parameter. If they land on the site that uses a first-party cookie with enabled browser tracking, then the fbclid query parameter is saved inside the  _fbc parameter.

It’s important to understand that not all your events will have _fbc parameters. Traffic from organic searches, google ads, or email campaigns won’t contain _fbc since interactions with the site don't happen on Facebook.

How is the Facebook event match quality score calculated?Copy link to this section

The maximum score you can get for the FB server event is 10. Getting to the ultimate point will be complicated. This score means that you have to send all user information parameters for your server events, and these parameters are sent on all occasions. 

For events such as PageView, where you do not have any user parameters, the match score will be around 4. Everything that you will be able to send is _fbp, _fbc, IP Address, and User-Agent.

How to increase Facebook event match quality scoreCopy link to this section

1. Set up a custom subdomain.Copy link to this section

If you decided to set up Facebook Conversion API through the Google Tag Manager, we recommend using a custom subdomain for the tagging server URL. This way, you can move from the 3rd party to the 1st party cookie. It will also help to increase tracking accuracy and set _fbp and _fbc correctly.  

2. Use data layer.Copy link to this section

Before setting up ss tracking or browser tracking, you need to have a proper data layer. This way, you can ensure that your trigger, variables, and tags will work correctly if the page URL, element ID, or CSS selector changes. 

3. Make sure to send all possible user information to the data layer.Copy link to this section

Here's an example. When a user logs in, you can send a data layer event that includes the user name, ID, and email. This way, you can increase the match quality of all events with these user data. 

Ask developers to set up a data layer or use a plugin for your CMS that generates a data layer. 

4. Check that there is no error with the server events you send.Copy link to this section

Facebook will decrease event match quality if you have any errors for the server events. Check this blog post that describes some popular Facebook CAPI issues and tips on fixing them. 

To find if there is any error, open the events manager and click on the diagnostics tab. 

5. Store user data.Copy link to this section

Let’s say users subscribed to a newsletter on your site. By default, you can send their email only when subscribe events happen. But there is a way to store user data in the browser. In this case, you can send their email as long as it’s stored in the browser. You can use data tags to store user data. Here is a more detailed explanation of what a data tag is and how to use the store data tool

5. Enrich user data.Copy link to this section

One of the best ways to improve FB event match quality is by enriching it with first-party user data. With the newest feature release of sGTM, it is now possible to store and enrich user data using Firestore and Google Sheet. Connecting server Google Tag Manager with Firesore or Google Sheet might seem a little bit complicated, but it gives you unlimited possibilities for improving analytics data.

The logic of enriching sGTM data using Firestore and Google Sheet is similar: assigning a unique identifier to a user and writing user data for Firestore or Google Sheet when user data is available, such as purchase events. Then extract user data using a unique identifier when you need it.

If you are interested in enriching sGTM data, check these articles: 

6. Event Enhancement.Copy link to this section

You can also enable Event Enhancement to use HTTP only secure cookie (gtmeec) in order to enhance event data.

When this feature is enabled tag will store user data in cookies and enrich events with user data when user data is not available. This way you can increase event match quality and as the results conversion attribution to campaigns. 

ConclusionCopy link to this section

We receive a lot of questions about the Facebook event match quality scores. But there is no way to say if the event quality score is good or bad. If the quality score on your server events is lower than 3, then it might be a red flag. 

Just try to send all the user information you have when this FB event happens. Of course, sending user data to FB should comply with the privacy policy and terms and conditions indicated on your website. You should follow GDPR rules and ask for user consent before tracking them or sending their data to Facebook. 

A lot of people are worrying when they have a match quality around 6. It’s an astounding number. Do not worry. Facebook is sending so many suggestions on improving quality match scores because they want to collect as much user data as possible. 

Suppose you send the most straightforward 4 customer data parameters (_fbc, _fbp, IP address, and User-Agent). Most likely, FB already has enough data to associate this event with a real user. If you add user email, then chances are even higher. 

Ultimately, if your goal is to increase the event match quality score, follow the tips described in this article. 

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