Session unification allows hits collected before the User ID is assigned to be associated with an ID.
In this article:Session unification is a User-ID setting that allows hits collected before the User ID is assigned to be associated with the ID, so long as those hits happen within the same session in which a specific ID value is assigned for the first time. When session unification is OFF, only hits that are collected when the User ID is explicitly assigned can be associated with an ID.
To turn session unification ON/OFF
When you set up the User-ID feature, session unification is ON by default. You can turn the setting OFF during set up, or you can follow these instructions to turn it ON/OFF anytime.
To turn session unification ON/OFF on a User ID property:
- Sign in to your Analytics account.
- Click Admin and navigate to the property you want.
- Click User ID.
- Click Step 2.
- Click the switch to toggle ON/OFF.
How session unification affects your data
These examples compare which sessions and session data can be associated with a user ID when session unification is either ON or OFF.
Although you can use Analytics for many different technologies and implement the User ID feature in many ways, these examples demonstrate session unification in a situation where Analytics is used on a website and the User ID is assigned through an account sign in.
In the illustrations, each session is represented by a rectangle, and the numbers indicate different sessions. A filled-in rectangle indicates when a user ID is assigned. For example, a user ID was assigned for the entire duration of sessions 3 and 6, but only for a portion of sessions 2 and 4. The dotted lines indicate which sessions (or portions of a session) are associated with a user ID.
When session unification is OFF
- Session 1: User visits your website, but there’s no account sign in. The user ID is not assigned, and no hits are associated with an ID.
- Session 2: User visits your website, and signs in to an account halfway through the session. A specific ID is assigned. Hits collected before the ID is assigned are not associated with the ID. Hits that are collected after the ID is assigned are associated with the ID.
- Session 3: User is signed in for the entire length of the session. The user ID is assigned, and all hits from the session are associated with the ID.
- Session 4: User is signed in when the session begins, but signed out halfway through. All hits collected while the user was signed in are associated with the ID. All hits collected after the sign out are not associated with the ID.
- Session 5: User is signed out for the entire session. No user ID is assigned, and no hits are associated with an ID.
- Session 6: User is signed in for the entire length of the session. All hits from the session are associated with the ID.
When session unification is ON
- Session 1: User visits your website, but there’s no account sign in. The user ID is not assigned, and no hits are associated with an ID.
- Session 2: User visits your website, and signs in to an account halfway through the session. A specific ID is assigned. All hits from this session are associated with the ID.
- Session 3: User is signed in for the entire length of the session. The user ID is assigned, and all hits from the session are associated with the ID.
- Session 4: User is signed in when the session begins, but signed out halfway through. All hits collected while the user was signed in are associated with the ID. All hits collected after the sign out are not associated with the ID.
- Session 5: User is signed out for the entire session. No User ID is assigned, and no hits are associated with the ID.
- Session 6: User is signed in for the entire length of the session. The User ID is assigned, and all hits from the session are associated with the ID.
Only hits prior to the first hit with User ID in the session are included in User ID views. For example:
- Hit 1– No User ID.
- Hit 2 – No User ID.
- Hit 3 – User ID set. First authenticated hit.
- Hit 4 – No User ID.
- Hit 5 – User ID set.
In the above example Hit 4 (an "unauthenticated" hit) will not be included in a User ID View since it doesn't come before the first hit with User-ID.
- Session unification is completed during daily data processing. Processing begins at 5am each day, based on the western most timezone selected in any reporting view that is associated with the property.
- In User-ID views, you may see higher direct sessions and direct revenue during intra-day dates because session-unification has not yet happened. This is because the campaign referral information is sent during the first hit of a session where the user has not yet logged in. The unification with the referral information happens daily at 5am based on the location of your western most timezone.