In response to Google’s recent announcement that they will no longer pass query data for organic search users that are logged into any Google products at the time of a search, we’ve been tracking what type of impact this may have on our ability to report metrics at the keyword level. Below you will see a chart which reflects a handful of sites we currently work with and the percentage of traffic from organic search that is reported in Google Analytics with the referring query “not provided”.

As you can see, prior to October 18, there was virtually no organic search results without referring query data. Starting on Oct 18, Google tested this new configuration on a small percentage of users. It appears that since Monday, October 31, 2012, Google has been rolling this out across their data centers. Currently we are seeing the effect vary by client from 4.5% up to 20.5%. We believe these differences are caused by differing demographics. For example, the client with minimal impact- 4.5% of organic search traffic, targets a mature (read “older”) segment, while the clients that are reaching 20% of organic search traffic coming from Google’s secure servers are much younger, primarily college age students.

These sample sizes are not insignificant. The average daily SEO traffic for the clients reflected in this chart is around 60,000 SEO visitors per day.

We’ve also noticed that it does not appear that Google has rolled out this change to all users, and may even vary the redirects for individual users based on browser. We will continue to monitor this and report our findings.