We’ve been working on a few projects recently where it transpired that a significant amount of AdWords traffic was being miscounted as Google Organic which meant skewed figures and incorrect conclusions.
The way Google Analytics tracks AdWords clicks is via the gclid parameter which is added to your landing page URL when you enable auto-tagging in AdWords.
If you don’t enable auto-tagging (and haven’t set up manual tagging) then your visitors will be miscounted as organic rather than paid and the number of AdWords “visits” being reported by Analytics will be a lot less than the number of “clicks”.
One of the major problems with the gclid parameter is that it’s stripped out of URLs quite often when 301 redirects are applied, so if you change your URL structure without altering your landing page URLs in AdWords then your traffic will be miscounted, unless you have built special 301 redirects which preserve the gclid parameter.
The way to track this is simple. Just load up Google Analytics and click on Traffic Sources > Adwords > Keywords and then the “Clicks” tab.
As you can see in the screenshot above, around 16,000 AdWords clicks are missing from the “visits” number which means they are misclassified as Google Organic.