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User ID changes before and after registration

  • 9 January 2023
  • 1 reply
  • 189 views

Below screenshot 1 is from a single session, however it has two user IDs before and after user registration on the app (“New user registered”). 

If I focus on user ID = 4837, its log starts only after registration and cannot tell what s/he did before that.

How can we prevent this happening? TIA. 

*I’ve used the same device for other user IDs.

 

1) single session across 2 user IDs

 

2) user ID 4837 log starts after registration 

 

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Best answer by Yuanyuan Zhang 10 January 2023, 21:42

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Userlevel 5
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Hi @Noa,

Thank you for reaching out. Happy to help!

From your description, it seems that your instrumentation is assigning user IDs to anonymous users and then assigning a new one after they register. 

Amplitude uses a system of User IDs, Device IDs, and Amplitude IDs to track unique users. A user can have multiple Device IDs and Amplitude IDs, but each unique user should only have one User ID. If it is changed, then Amplitude will treat that new User ID as a different user. It is fine not to set a User ID -- you should NOT set a User ID for anonymous users: https://help.amplitude.com/hc/en-us/articles/206404628

You can read more about how we track unique users here: https://help.amplitude.com/hc/en-us/articles/115003135607-Tracking-Unique-Users.

Hope this helps, and please let me know if you have further concerns.

Best regards,
 

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