Looker Stuido Visitor count aggregation error?


I’m testing looker studio for a client of mine and while, session counts and page views look correct the visitor counts in Looker are way higher than they appear within Piwik’s own reporting tool. (For reference I’m comparing the built in Piwik report for Audience Overview).

If I do a simple Visitor count for a day everything is fine. For 3rd June I see 19,504 visitors in both platforms, but if I do a visitor count for the whole of June I see 372,094 within Piwik Pro but 519,947 in Looker Studio. This to me sounds like an aggregation issue with visitors being double counted in Looker.

Doing the same comparison with Sessions or page views gives me the same result on both platforms so it seems to be limited to just visitors.

Has anyone else noticed this?


Welcome to the community!

Could you provide me with the definition of the report that you created? What metrics and dimensions did you use?

Hi @Dave_Wyborn,

Apart from the things mentioned by Adam - could you also check the version of your Looker Studio connector?

Hi. thanks for the replies.

@asinior I’m just using a simple scorecard so no dimension and the only metric is ‘visitors’. As I said before if I set the metric to sessions I get the numbers I expect.

@anthonybartczak I’m using v 1.3.0 which I believe is the latest release.

Many thanks

Hi @Dave_Wyborn!

Just FYI - we’re still looking into this issue but it looks like it’s connected to how we pull metrics that are later aggregated (e.g. avg, min, max) inside Looker Studio. I will probably add more context once we confirm the theory.

And you are correct - this issue is indeed limited to certain metrics.

Great. Thanks for the update.

In the meantime, you can try using the visitor ID dimension and “Count distinct” aggregation, it should show the proper value.