Yes, it is possible that Google Analytics 4 (GA4) may not get the right referral due to multiple websites. This is because GA4 uses the referrer URL to determine the source of traffic to your website. If a user visits your website from a link on another website, the referrer URL will be the URL of that other website. However, if a user visits your website from a link on one of your own websites, the referrer URL will be the same as the URL of your website. This can make it difficult to track the source of traffic if you have multiple websites.
There are a few things you can do to ensure that GA4 gets the right referral for your multiple websites:
- Use cross-domain tracking. Cross-domain tracking allows you to track users who visit your websites from different domains. This can be done by adding a special parameter to the referrer URL when a user clicks on a link from one of your websites to another.
- Use referral exclusion. Referral exclusion allows you to exclude certain domains from being counted as referrals. This can be useful if you have multiple websites that link to each other, as it will prevent these visits from being counted twice.
- Use custom dimensions and metrics. Custom dimensions and metrics allow you to track specific data that is important to your business. You can use these to track the source of traffic even if the referrer URL is not correct.
If you are still having trouble getting the right referral for your multiple websites, you can contact Google Analytics support for help.
Here are some additional things to keep in mind:
- GA4 does not support cross-domain measurement by default. You will need to enable it in the Admin settings.
- Referral exclusion is limited to 50 domains per data stream.
- Custom dimensions and metrics can be a powerful way to track data that is not natively supported by GA4. However, they can be complex to set up and use.