Ever since March 2004, I have been comparing analytics software built by the same company. The first entry I have on this was named Comparing Web Traffic Between Different Web Analytictical Tools which shows the huge gap in traffic when comparing Urchin 3.x to Urchin 5.x. Then the topic came up again in January 2005, with an entry named Web Analysis Tools & Consistancy. Which led me to an entry in late May of 2005 where I said, Web Analytics Needs Standards Bad.
So when Google Analytics came up, I signed up and let the data collect. Keep in mind, Google Analytics is Urchin. The differences are; (1) its a half of a version newer and (2) one is server side tracking (logs and 1st party cookies) and the other is simple JavaScript tracking (3rd party cookies). Then yesterday, I did a comparison of my trusted Urchin 5.7 package against Google Analytics for the month of December. I came up with a 20%, 19.79% to be exact, increase in traffic for the Urchin 5.7 tracking over Google Analytics. Ill post the daily increases for December in the extended entry area, you will notice it was as low as 5% and as high as 30%.
For a visual reference check out this chart, you can click on it to enlarge. The red is Urchin and the blue is Google.
I started a thread on this topic at our forums and Matt, md_doc explains why this may be the case. He says;
Using logs you get information that you would not get with javascript... like when someone that has javascript disabled comes to your site, or when a robot parses your site.
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? :)
Forum discussion at Search Engine Roundtable Forums.December Shows Urchin Has Higher Visitor Counts then Google Analytics
Thu 12/1 21.63% Fri 12/2 28.11% Sat 12/3 12.20% Sun 12/4 12.87% Mon 12/5 12.33% Tue 12/6 24.29% Wed 12/7 25.66% Thu 12/8 24.66% Fri 12/9 19.76% Sat 12/10 19.67% Sun 12/11 5.95% Mon 12/12 24.51% Tue 12/13 22.20% Wed 12/14 25.83% Thu 12/15 24.56% Fri 12/16 23.32% Sat 12/17 20.24% Sun 12/18 10.42% Mon 12/19 16.84% Tue 12/20 20.50% Wed 12/21 18.96% Thu 12/22 21.03% Fri 12/23 29.67% Sat 12/24 18.34% Sun 12/25 13.66% Mon 12/26 17.03% Tue 12/27 19.73% Wed 12/28 20.93% Thu 12/29 18.68% Fri 12/30 24.90% Sat 12/31 14.94%
