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jacquesm: Could you please comment more on the inaccuracies you notice from Google Analytics?

by asb 17y ago

jacquesm 17y ago
If I take my log files and put them side-by-side with google analytics after synchronizing the clocks (analytics switches days at 9am in the morning here) I am sometimes off by as much as 100%. It's been bugging me for the longest time and I can't find a conclusive cause for the discrepancy. More interesting is that when I put the analytics numbers next to the adsense numbers and the log files is that the adsense numbers (pageviews) tend to be more accurate than the analytics numbers. For performance reasons the analytics tags are at the end of the page, the only plausible explanation I can find for all this is that users click links so fast that they never wait for the page to load fully before they move on. Because the ad tags are higher up in the page and therefore load earlier that just might explain part of the gap. But definitely not all of it.
- mrkurt 17y ago
  You'd be surprised how big of deal GA tag placement can be. We see vastly different stats when we have them in the header vs the bottom of the page. It has something to do with previous page elements blocking the page render. Also, you're accounting for spiders in your logs, right?
- tptacek 17y ago
  You're surprised that self-reported Javascript-driven stats are less reliable than server logs?
  - jacquesm 17y ago
    Yep. See, if they would be underreporting, I would have all kinds of plausible explanations for that. But they are overreporting, on some days as much as 100% and I really don't see how google can see traffic on their tags that I don't have in my logs.
    - jongraehl 17y ago
      I wonder if the javascript sends to GA each time a page is reviewed (e.g. "back") without being fetched anew from your server.
      - jacquesm 17y ago
        That could be, but then I'd just see more pageviews, not more uniques, and it is with the uniques that there is a serious problem. Adsense pageviews are pretty much dead on, GA pageviews are 'spotty', sometimes more correct than at other times, GA uniques are simply unreliable. What I don't get is how adsense seems to get it right wrt to pageviews and GA does not. Adsense only reports impressions though, not uniques so I can't compare that metric between adsense and analytics.

jacquesm: Could you please comment more on the inaccuracies you notice from Google Analytics?

by asb 17y ago

jacquesm: Could you please comment more on the inaccuracies you notice from Google Analytics?

If I take my log files and put them side-by-side with google analytics after synchronizing the clocks (analytics switches days at 9am in the morning here) I am sometimes off by as much as 100%. It's been bugging me for the longest time and I can't find a conclusive cause for the discrepancy. More interesting is that when I put the analytics numbers next to the adsense numbers and the log files is that the adsense numbers (pageviews) tend to be more accurate than the analytics numbers. For performance reasons the analytics tags are at the end of the page, the only plausible explanation I can find for all this is that users click links so fast that they never wait for the page to load fully before they move on. Because the ad tags are higher up in the page and therefore load earlier that just might explain part of the gap. But definitely not all of it.

mrkurt 17y ago
You'd be surprised how big of deal GA tag placement can be. We see vastly different stats when we have them in the header vs the bottom of the page. It has something to do with previous page elements blocking the page render. Also, you're accounting for spiders in your logs, right?
tptacek 17y ago
You're surprised that self-reported Javascript-driven stats are less reliable than server logs?
- jacquesm 17y ago
  Yep. See, if they would be underreporting, I would have all kinds of plausible explanations for that. But they are overreporting, on some days as much as 100% and I really don't see how google can see traffic on their tags that I don't have in my logs.
  - jongraehl 17y ago
    I wonder if the javascript sends to GA each time a page is reviewed (e.g. "back") without being fetched anew from your server.
    - jacquesm 17y ago
      That could be, but then I'd just see more pageviews, not more uniques, and it is with the uniques that there is a serious problem. Adsense pageviews are pretty much dead on, GA pageviews are 'spotty', sometimes more correct than at other times, GA uniques are simply unreliable. What I don't get is how adsense seems to get it right wrt to pageviews and GA does not. Adsense only reports impressions though, not uniques so I can't compare that metric between adsense and analytics.