Keep Your Old Google Analytics UA Tracking Code With New GA4 Code To Run In Parallel

With Google Analytics rushing folks on Universal Analytics to set up Google Analytics 4, many are asking if they should run both UA3 and GA4 code at the same time. The answer, in my opinion, is yes, at least until UA3 stops tracking.

It is interesting because we have different responses from two different Googlers on different sides of the company.

Ginny Marvin, the AdsLiaison, who works on the ad side of search, said on Twitter to keep both, UA3 and GA4, going at the same time. She said “For now, it’s best to keep existing UA instances running & set up a GA4 property to start collecting data in parallel.”

John Mueller who works on the organic side of search, said he is not sure but he running both would slow things down. He said “I have no idea, but I imagine you could. Some sites have multiple analytics/metrics setups in parallel — it slows things down though.”

Here are those two tweets:

For now, it’s best to keep existing UA instances running & set up a GA4 property to start collecting data in parallel.
This is a step-by-step setup overview: https://t.co/52WekstCo7 Step 4 covers site tagging for data collection: https://t.co/fh97ERAwL3

— AdsLiaison (@adsliaison) March 18, 2022

I have no idea, but I imagine you could. Some sites have multiple analytics/metrics setups in parallel — it slows things down though.

— 🐐 John 🐐 (@JohnMu) March 18, 2022

I personally have both running in parallel – I think any slow down is worth it – at least temporarily – to see how both UA3 and GA4 compare day-to-day and in general.

Forum discussion at Twitter.