Facebook Event Match Quality – what it is and how to improve it

If you ran ads on Facebook, you probably faced the fact that not all events are accurately transmitted, and the results of campaigns do not always meet expectations. One of the key indicators that you should pay attention to is Meta Event Match Quality, or the quality of event matching. Simply put, this assesses how well Meta can "recognize" your users from the data you transmit. The higher this score is, the more accurately your analytics work and the better Facebook "understands" who to show ads to. In this article, we will tell you how this mechanism works, what data should be transmitted, and how to improve the comparison quality, even if you are not a technical specialist. Let's figure it out together!

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. 

Meta Event Match Quality (EMQ) is an essential metric that reflects the accuracy of user data parameters associated with server events transmitted to Meta. This accuracy impacts how precisely server events are matched to user profiles on Meta.

Higher EMQ scores for server-side events increase the likelihood of Meta correctly linking the server event to the corresponding user profile. This linkage directly influences the conversion attribution of your Facebook ads campaigns. The higher the EMQ, the more accurate conversion attribution becomes.    

Having a high Event Match Quality score also helps Meta better understand what your customers like and how they behave. This means Meta's ad system can better show your ads to people who are similar to your customers and more likely to be interested in your products. 

Meta Event Match Quality is scored from 0 to 10, which reflects the quality of customer data you send for a particular server event and how often these events are linked to Meta accounts.

These event match quality scores are available for all standard and custom web activities, like viewing pages, adding items to a cart, or making purchases. These scores are based on the most recent 48 hours of data, so regularly sending event data is crucial to maintaining current and accurate event match quality scores.

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 stape.com, 1 for app.stape.com, 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.

Event Match Quality helps with the following:

• Improved targeting. Higher match quality means that your ads reach people who are more inclined to engage with them based on previous interactions tracked through matched events.
• Better cost efficiency. With better targeting and attribution, you should see better ad performance, which results in a lower cost per action (CPA).
• Better attribution. When the events are matched to the users accurately, Facebook can better attribute conversions to your ads. This will give you better insights into the effectiveness of your campaigns. 

Enhancing the quality and completeness of the PII you provide will significantly improve Event Match Quality. This will lead to more effective and efficient ad campaigns.

Event Match Quality depends only on Personally Identifiable Information (PII). PII plays a crucial role in determining Event Match Quality. PII includes data points like email addresses, phone numbers, and other identifiers that help Facebook match the event data you send with actual user profiles. The more comprehensive and accurate the PII you provide, the higher the likelihood that Facebook can match those events to the correct users.

Maintaining a high volume of rich PII sent to ad platforms often becomes difficult when users return on new devices or start fresh sessions where those parameters are temporarily missing. You can solve this by implementing deterministic server-side matching, which captures persistent identifiers and automatically enriches downstream events with the missing PII, meaning server-side user stitching across sessions happens seamlessly under the hood without relying on manual tag configurations.

Please see the table below, which shows the PII that impacts event 

The parameters are described in the Meta documentation in the Customer Information Parameters on this page. You can click on any Customer Information Parameter to see its details. 

All parameter tags are hashed in GTM automatically; if they are needed for a parameter, you do not need to hash them on your own.

Facebook tags automatically collect basic parameters like FBP, FBC, Client IP Address, and Client User Agent, but you must manually send the other available ones. Always send customer data when you have access to it. For example, when a user creates an account or authorizes on your website, you will get access to the user's email. In this case, you must send user emails with all the events. It will improve the match quality of events like purchases in eCommerce.

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.

Event data you need to collect to reach the optimal quality score falls under data privacy regulations. Let's look at strategies to help your user data management practices align with GDPR, ePrivacy Directive, CCPA, and other applicable privacy regulations. 

Under GDPR and other EU data protection regulations, you must obtain end-user consent before sending data via our SDK. Thus, you must ensure that your SDK implementation meets these consent requirements. Implement clear and concise consent forms informing users about the collected data. Inform users the purpose of data collection and how it will be used for data matching. Ensure that consent is detailed and that you give users the choice to opt in or out of specific data processing activities.

Define what data you need for your event matching and avoid collecting any excessive data. Make sure each type of data you collect serves a clear purpose. When you use the FB SDK for App Events, Meta business terms require that you have an appropriate legal basis for collecting and processing users' information.

Before you send data to Facebook for matching, use hashing algorithms to anonymize personal user information. This will help you protect user data while keeping event match quality high.

By the way, the Stape Anonymizer power-up is available for all Stape users. Its main goal is to remove or anonymize user data from GA4.

Build privacy into how you collect and handle data from the start. Regularly review your data practices to meet GDPR and other legal standards. Revise your privacy policies to clearly explain how you collect, use, and share user data for event matching. Being open about your data practices builds trust and helps you meet GDPR's rules for clear communication with users.

Privacy laws are constantly changing, so keep up with the latest updates to GDPR, the ePrivacy Directive, and other related regulations. Adjust your business processes to stay compliant and keep your event match quality on track. If you work with data that falls under privacy regulations, having a strong legal team is always safer to help you navigate the ever-evolving rules and laws.

Use Facebook's tools, like the Conversions API, to better manage what data you share and ensure it meets your privacy goals. This way, you can improve event match quality without compromising user privacy. You can also explore Shopify Facebook CAPI setups to integrate directly with your store. 

Keep an eye on your event match quality using Facebook's reports, but do it in a way that respects privacy. Check your match rates regularly and adjust to improve results while protecting user data.

These best practices will help you balance event match quality and privacy regulations. Now, let's move on to our next point: the influence of iOS privacy changes on Facebook event match quality.

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.

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. 

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 will 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. 

Facebook will decrease event match quality if you have any errors in the server events. 

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

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. 

There are a few ways to enrich the user data with Stape's solutions:

• Enricher power-up 

When an event is sent in your sGTM container, the Enricher checks whether first-party data has already been stored for that user having one of six supported identifiers (email, cookies such as _sbp, FPID, _ga, _dcid, and X-Stape-User-Id). 

If matching data is found, the Enricher automatically adds the missing information (such as hashed first name, last name, email, or phone number) before the event is sent to Meta.

In this way, the Enricher helps improve the quality of data sent to advertising platforms and can help increase event match quality.

The Enricher power-up is available on the Pro plan and higher. For Custom plans, Enricher is available at a separate price after consulting with our sales team. However, there are also alternative ways to enrich user data. 

• Store and retrieve user data using Firestore or Google Sheets 

The logic of enriching sGTM data using Firestore and Google Sheets is the following: assign a unique identifier to a user and store available user data in Firestore or Google Sheets (for example, during purchase events). Later, when another event occurs, the same identifier can be used to retrieve the stored information and enrich the event before it is sent to Meta.

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

• Write data from server Google Tag Manager to Google Sheets
• Read data from Google Sheets to server Google Tag Manager
• Read data from Google Sheet to server Google Tag Manager

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. 

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 Meta Event Match Quality score, follow the tips described in this article.