At Search Engine Roundtable, one of my favorite sites, Rustybrick posted an interesting article about a comparison between Urchin Server Side and Google Analytics where he asks:
Can you believe that it can affect on average, 20% of the visitors of this site? Who are you that are blocking those cookies? Do you even know you are blocking them?
Rustybrick did a comparison of his Urchin 5.7 package against Google Analytics for the month of December and came up with a 20% increase in traffic for the Urchin 5.7 tracking over Google Analytics. He made it visual with a chart. He (and me too) wonders about the huge gap between both tools and some discussion came up in comments and his forum.
As an user of the Urchin Software I had the same idea and inserted the Google Analytics snippet to the sourcecode of a anonymous domain. Below you can see my results for month december. It’s quite astonishing, comparing the two charts gives nearly no differences between Urchin Software and Google Analytics. The stats had to be synchronized in time, as local time here in germany differs by 9 hours with google time.
Result: The statistics differ by approximately 0,5%, that’s an unbelievable strict conformity.
The charts show daily visitors for december 2005. The Domain is located/served in Germany.
One additional remark about Urchin Software. When campaign tracking is enabled and cookie logging is used i am quite sure that there will be no bots that interfere with user stats.