ZydoSEO - 9:23 pm on Feb 2, 2013 (gmt 0)
Hello BobMM. Welcome!
I have to agree with Ted. Though many sites might use GA, many still do not. This would be a very poor choice for a ranking signal since they do not have access to the same data for a large percentage of sites on the web. Chances are slim to none that any data that might be collected by GA on your site would be used to influence your site's rankings.
What date did you experience the loss in traffic? How big was the drop? Did you loose traffic from a small percentage of URLs on your site or did you seem to lose traffic across most of your URLs? Did you lose traffic for a small number of key keyword phrases or did you lose traffic across most all of your keyword phrases? Were there any major changes made to the site (redesign? changes to URLs? Changes to content? etc.) in the weeks or even couple of months leading up to the noticeable drop in traffic? Was there any link building going on in the weeks or couple of months leading up to the drop in traffic?
These are some of the questions I'd ask yourself to try to pinpoint what might have lead to the drop in rankings/traffic.