We have noticed that our count for traffic and impressions stay within the same range as GA and is usually 1-5% higher. However when it comes to engagements and conversions we usually see about 50% higher on our end.
In some cases an engagement can be tricky because the "click engagements" is the one that is going to be reported to google analytic because the customer actually clicks on something on the overlay however the view engagement is not as it is only counted within Justuno if a user views the overlay for more then 8 seconds.
We also checked one more stat to see if GA was off and this one is arguably the most important one - conversions
What we found is that GA is not accurate at all when it comes to certain stats. GA reported 139 transactions for one of our clients when over the same time period his store sold and shipped 252 orders! Our JU conversion code reported 217.
We have a couple theories why this could be happening:
- GA is filtering out bot and crawler traffic, this could explain engagements however this would not explain the conversions because i doubt the bots are buying actual products
- Some people use "do not track" and other extensions to block GA and other commercial trackers from fingerprinting their browser and tracking them across sessions to prevent targeted ads. Justuno is not as known as GA and probably gets blocked less.
- GA is not actually that accurate because of the way they designed it, there would be so much data for them to store that they actually down sample if you have more then 500,000 sessions in your report, you can read more about GA sampling here - https://support.google.com/
- Some browsers (mobile browsers ) or some software platforms and operating systems (Ubuntu for example) might be blocking GA calls on purpose or not sending them properly due to technological problems or competitive business practices