Total of UTM medium visitors not equal to total visitors

Hi there, 

When I try and track where all my page visitors are coming from by grouping by utm_medium, I find that summing of the number of unique visitors from across all mediums (including (none)) gives a total which is far below the total number of unique visitors to the site.

Please can you help explain if I have done something incorrectly or why this is?

Thank you!

3 replies

Userlevel 4
Badge +9

This is completely expected behaviour @B Analytics . It’s perfectly possible for a single unique user to have mutiple utm_medium values (same goes for other user properties)...for example, I could go to my website from a PPC ad, then come back again later from an affiliate link. When you create a table with the utm_medium values as rows, that single user will count in multiple rows, so the sum of the rows won’t add up to the (de-duplicated) grand total.


Userlevel 4
Badge +9

Apologies….ignore that, I’ve just noticed you said the sum of the rows is below the grand total. The comment I just made applies the other way around 😀

Userlevel 4
Badge +9

Funnily enough I’m seeing the same behaviour….I’ve used a breakdown by Platform in full knowledge that we currently only push “Web” into Amplitude.

Same as you, you can clearly see the sum of the rows (only one row in this instance) is less that the grand total. Which makes zero sense here, they should be the same.

Hopefully someone from Amplitude can clarify…@Denis Holmes perhaps?