Google search volume overstated in Google Analytics by using 6 month cookies

Interesting post about Google Analytics.  Seems a 6 month cookie is used by Google, so that any visit for up to 6 months after the cookie is set, no matter where the visit is from, is attributed to Google.com search.

Comparing the stats for Toprural delivered by Google Analytics with his own 3rd-party solution, he finds that, while his own system (AT Internet’s XiTi) says 37.8% of visitors come via Google, GA says it’s 71.8%. The core of the problem, he discovers, is the good old cookie window. It turns out the default cookie window Google ascribes to visitors that arrive on a site via Google is six months. Six months!

So, every visit a user happens to make to a site for the six months after having once visited that site via Google is ascribed to the search engine. The standard window for display media is 30 days, a sixth of the length Google has opted for, while we’re typically asked to assign search cookie windows of a couple of days at most.

Read the full article here.