I'm doing some research into the SEO of one my websites and looking at different keywords and the search traffic they generate.
Let's say I have a search term I'm ranked number one for a keyword and looking at the following reports reveals different results:
Google Analytics reports 6 users visited on a particular day from a search term.
Google Webmaster tools reports I am ranked number one for the same search term and that 22 people clicked it on that same day.
Google Adwords traffic tool estimator reports the daily impressions would be zero for that search term (even when max CPC is 99999 and avg. position is 1).
Is the Adwords traffic estimator a valid tool for SEO research? And why is there such discrepancies between my Google Analytics and Google Webmaster?