Why did these users get different amplitude_id's?

  • 16 January 2023
  • 3 replies

We believe we are having some bots visiting one of our pages and we notice that such "visitors" have been recently identified with different amplitude_id's, see example in screenshot ; 


This pollutes are charts quite a lot as we are calculating user-level conversion rates in a funnel and the denominator is way too high because these are all counted multiple times instead of once. 

Can you please explain why these users all get a unique id?


Best answer by Yuanyuan Zhang 19 January 2023, 15:49

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Userlevel 6
Badge +9

Thanks for reaching out here @Katrien Baert. Here’s more information about identifying users from our help center - link. This includes step-by-step information on how user IDs work. Please keep us posted if this helps.

Hi Jeremie, no this doesn't really help me understand why the specific users in the screenshot are considered different by Amplitude. The key question is how Amplitude ID's are generated. 
In segment these "visitors" all have the same anonymous id. 

Userlevel 5
Badge +5

Hi @Katrien Baert

Thanks for the post! 

This doc explains How Amplitude assigns Amplitude IDs in details with examples. Your mentioned these "visitors" all have the same anonymous id in Segment, so I would assume they are one unique anonymous user. Without looking into the data, my first thought is that these users may have been assigned different Device IDs when the events were sent from Segment to Amplitude. 

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 can only have one User ID. In your case, this user does not have a User ID, so Device ID is used to identify users. Each Device ID will be assigned an Amplitude ID. 

Please kindly have a look at your project data and let me know if this is what happens. If yes, then I suggest first checking with Segment and making sure the events of one unique anonymous user are sent under one Device ID. 

I hope this helps. Looking forward to hearing back from you!