Matomo Numbers are lower than from Google Analytics (UA)

Dear Matomo Community,

right now we have the problem, that we did a comparison between Matomo and Google Analytics.
For the first time we have the problem, that the numbers from Matomo are lower, than from Google Analytics. Does anyone have here an idea, why is that? We need an explanation to justify Matomo to our customers.

Frequent issues:

  1. GA was tracking twice because of a double tracking code (it’s an embarassingly frequent issue)
  2. GA was tracking more than one website and/or Matomo is not installed on every website

It’s 99% a technical issue.

Look at the hostname dimension in Google Analytics, that will probably help in pinpointing the exact cause.

Not sure why you are still using GA Universal, it’s been discontinued.

You should not look at the data in GA Universal unless it’s past data prior to July 2023. But anything after July 2023 it’s not tracking it anymore and it’s already discontinued. It is to be expected that GA UA will also be removed at some point. (I highly doubt that Google will keep its access after it’s been discontinued)

You should be using GA4 and if you’ll see mismatches in GA4 vs Matomo it’s a few reasons too, like Attribution model differs in GA4 etc. As of now, I’ve found GA4 to be sometimes not as accurate in terms of full conversion paths or traffic sources.

Matomo does real time reporting and shows full conversion path.