It's not uncommon that Amplitude's numbers may differ from other vendors (e.g. Google Analytics, Mixpanel, etc). Many factors could impact your data, and the purpose of this article is to help you understand the biggest factors. Throughout this article, we will assume that you understand how Amplitude tracks users and sessions. Otherwise, the articles provided at the bottom will explain how Amplitude tracks users and sessions.
If you have taken all of the following factors into consideration or need further assistance, please contact us here.
Table of Contents
Quick Checks
Here are some quick questions to ask before diving into detail. Questions you answer "No" to are factors that could cause a discrepancy between your user numbers, session numbers, and other metrics. Let OV (Other Vendor) represent the vendor that you are comparing Amplitude numbers to:
1) Do the time zones between Amplitude and OV align?
- If you answered "No", then make sure to align the time zones before comparing numbers. Data ingested by Amplitude are timestamped in UTC, but you can customize the time zone within our UI.
2) Do the events you currently track in Amplitude reflect what you're tracking in OV?
- If you answered "No", then it's likely that there will be a discrepancy between your users and sessions numbers, as both are dependent on the events being tracked.
3) Do Amplitude and the OV block the same web bots and scrapers?
- If you answered "No", then it's likely that there will be a discrepancy between your users and sessions numbers. Note: Amplitude currently blocks any data with "Googlebot" in the User-Agent.
4) Do the OV and Amplitude define the metric of interest the same?
- If you answered "No", then it's likely that there will be a discrepancy since Amplitude and the OV define the metric differently.
5) Does the OV merge users like Amplitude does?
- If you answered "No", then depending on how the OV merges its users, it is possible that there will be a discrepancy between your users and sessions numbers since the user identification differs.
6) Is the session timeout window the same between Amplitude and the OV?
- If you answered "No", then it's likely that there will be a discrepancy between your sessions numbers. Note that if you are tracking data via the Amplitude SDKs, then the default session timeout windows are 30 minutes for web and 5 minutes for mobile. These thresholds are customizable in Amplitude, so please confirm with your developer whether they have been customized.
Google Analytics
Sessions
Though Google Analytics and Amplitude track sessions similarly, the following table outlines factors that cause a discrepancy in your session numbers.
| Scenario | Amplitude | Google Analytics | Source |
|---|---|---|---|
| Time hits midnight | Session continues | The current session ends at 11:59 PM and the new session starts at 12:00 AM. | See "Time Based Expiration" |
| Campaign source changes | Session continues | New session begins even if it is within the 30-minute threshold. | See "Campaign Based Expiration" |
| Session Event Limit | No limit | After the first 10 events, tracking is limited to 1 event per second. | See "Events Per Session Limit" |
Helpful Articles
Here are some articles you can read to learn more about how Amplitude tracks users and sessions.
Users
Sessions