Why is my MTU count higher or lower than the user count I see in my downstream destinations/other tools?

Comparing numbers between any two end-tools (or between Segment and an end tool) is rarely going to produce identical numbers. Each tool accepts and defines incoming data slightly differently, and they will not always match 100% depending on what types of data the tool accepts.

For example, consider these instances with some of our most popular destinations:

Google Analytics:

  • When sending page views from one of Segment’s server-side libraries, a url property is required. Otherwise, Google Analytics will silently reject your page event.

  • It is against Google’s terms of service to pass Personally Identifiable Information (PII) to your Google Analytics reporting interface. For that reason Segment will never pass anything from an identify call to Google unless you specifically tell us to.

  • If you want to pass the id from your identify calls to Google Analytics - enable Send User-ID to GA in your Advanced Google Analytics settings on the Segment destinations catalog.


  • By default, Segment won’t send standard page or screen calls to Amplitude. However, you can enable sending page and screen calls with the following destination settings, which you can find under the “Advanced Options” tab.

  • If you’re using a server-side library or the Segment HTTP API to send events or traits about anonymous visitors, Amplitude won’t automatically be able to identify that anonymous user as being the same person when they log in. To have Amplitude connect the dots, when you call .identify() on user log-in, you should include both the anonymousId you were using before the user logged in, as well as their userId.

  • For Amplitude to associate both client-side and server-side activity with the same user, you will need to pass the same deviceId to Amplitude. Otherwise, Amplitude will create two users - one associated with your deviceId and another user associated with your Segment anonymousId.

Please contact our support team for further inquiries about a specific tool you have questions about to ensure there isn’t an implementation error.

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