I see questions like this a lot: http://moz.com/community/q/webmaster-... - people are wondering if Webmaster Tools Average Position Data is wrong or accurate. The issue is, you can not look at it the same way as rankings. In this video I explain the differences between webmaster tools average position and rankings. There's some actionable tips for how to use each metric.
Things mentioned;
Great post by Jason Acidre
http://kaiserthesage.com/increase-sea...
Google Webmaster Tools
https://www.google.com/webmasters/tools/
The Ultimate List Of Rank Trackers
http://www.evolvingseo.com/2012/01/24...
Moz Ranker Tracker
https://moz.com/researchtools/rank-tr...
Authority Labs
http://www.evolvingseo.com/authority-...
Wistia - Getting Loose On Camera
http://wistia.com/learning/get-loose-...
And also, Google's Documentation on The Search Queries Report;
https://support.google.com/webmasters...