0

I'm migrating a high-traffic site from Classic Analytics (ga.js) to Universal Analytics (analytics.js). Both setups have been running in parallel for the past few days: ga.js is hard-coded on the pages (i.e. "_gaq" calls) and analytics.js is running through Google Tag Manager (GTM) with the standard integration for pageviews. Furthermore, both GA properties and views are configured exactly the same, and there are no interactive events (or similar) that could be causing big discrepancies.

There are some really strange discrepancies in the data, which I can't fully explain. For example, looking at yesterday's numbers, analytics.js reports:

  • 4% more sessions (~5,000)
  • 1.5% more users (~1,500)
  • 2% less pageviews (~7,500), and mostly flat unique pageviews
  • 6% less pages/session (2.69 vs 2.85)
  • 10% lower avg. session duration (00:02:31 vs 00:02:48)
  • 2% higher bounce rate (50.4% vs 49.4%)

I started drilling down into the reports and, so far, the biggest differences I can find in the analytics.js property are:

  • 15% more Direct sessions (~3,200)
  • 115% more sessions from "UC Browser" browser (~3,500)
  • 130% more sessions from "level 3 communications inc" ISP (~2,100)
  • 320% more sessions from the city of Putney (~1,700), with the majority of the increase attributed to "UC Browser"
  • 200% more sessions from Dubai and Beijing.

While I know analytics.js is supposed to be better, I'm having a very hard time explaining such large discrepancies, especially when it comes to the higher sessions, lower pageviews and time on site: these are moving in contradictory directions.

I would really appreciate any ideas on the following:

  1. How is it possible that I'm seeing so many more sessions, but less pageviews?
  2. Why is avg. session duration drastically different?
  3. Are there any other factors that could be causing such discrepancies? Especially the inflated session number.
  4. Should I move analytics.js entirely out of GTM?

Any other ideas are greatly appreciated.

1
  • 4% more sessions (~5,000)
  • 1.5% more users (~1,500)
  • 2% less pageviews (~7,500), and mostly flat unique pageviews
  • 6% less pages/session (2.69 vs 2.85)
  • 10% lower avg. session duration (00:02:31 vs 00:02:48)
  • 2% higher bounce rate (50.4% vs 49.4%)

i wouldn't name it big difference, specially based on the data from one day. Beside of this, the more you drill down your data gotten from such short time frame, the more discrepancies you get.

yes, universal track on slightly other way as classic, specially going about session length . Take it easy, check twice your setup, and compare much bigger data pieces (much longer time frames).

This thread could be helpful too. And this, as an example, what could be the cause of discrepancy.

0

My first thought would be that your events are out of whack.

Events can instigate Sessions, and affect Session Duration. If one of these accounts is receiving events, but the other isn't, I would expect the former to receive more Sessions, and have a greater (or at least slightly different) Session Duration.

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.