A self-referral is referral traffic that originates from pages within your own domain. In general, self-referrals indicate that there are Analytics implementation problems on your site.
If you're receiving self-referrals, that may mean that traffic to your site is being attributed incorrectly, or that your session count is inaccurate. There are a few different implementation problems that can cause self-referrals.
Common self-referral causes
When a user visits your site, the Analytics tracking code looks at the referring page to determine how to attribute that user's traffic source.
But let’s say that one of your landing pages isn’t tagged with Analytics and that a user clicks an ad to start a journey on your site. To Analytics, it appears that the first hit in the session is the second page visited on your site, and it appears that the referrer is your landing page. As a result, you get a self-referral.
Adding your domain to the referral exclusion list will appear to get rid of self-referrals caused by untagged landing pages. However, in this case, the referral exclusion list will attribute traffic from your own domain as direct traffic. The correct attribution is still missing. Since some direct traffic is normal for most websites, it also becomes difficult to distinguish between direct traffic and lost attribution. Again, the solution is to tag your landing pages.
Referral exclusions are discussed in the next section.
Universal Analytics includes your site’s domain in the referral exclusion list by default, so cross-subdomain tracking should work with no additional set up.
However, if your site has user journeys that cross subdomains, and the referral exclusion list does not include your site’s domain, then you can get self-referrals, as well as invalid extra sessions in reports. To fix this, make sure your domain is in the referral exclusion list.
Tracking web properties across multiple domains requires special configuration.
The default cookie configuration in the Analytics tracking code supports cross-subdomain sessions. If you’ve changed your tracking code to use special cookie settings, it’s critical that you understand what your changes do, and that you make these changes consistently across your entire site.
Learn more about tracking code cookie settings in the Analytics developer guide.
You can use Google Tag Assistant Recordings to see if you have self-referrals. Tag Assistant Recordings can tell you where a user’s session might break in subdomain or cross-domain tracking cases. It can also tell you whether your pages are properly tagged or not.
See an example Tag Assistant Recordings report that shows what it looks like when cross-domain tracking is not set up properly. Tag Assistant Recordings will give you a similar alert on other causes of self-referrals.