RockSolidWes - 10:02 pm on Dec 19, 2012 (gmt 0)
Your CTR may be very high, but it may be a result of being at the top of the page OR high on Google's search partners or it may just be high on the broad match.
That being said, Google normalizes your stats. That means if they show your ad on the side (as oppose to the top) they monitor your stats. If you are high because you out bid your competitors BUT fail to complete when on a normalized position (side bar) your quality score can suffer.
Your CTR is may be high only because you out bid your competitors but your ad is not competitive when normalized and placed on the side.
In addition to that, you may have a poor performing CTR when the exact match is considered. You may have a high CTR a broad search terms BUT for the exact match only you may register few impressions and no clicks or few clicks. This will drag your QS down even though for that keyword you have a high CTR.
Try this: ON the keyword tab segment by 'Top Vs. Other' and 'Click type' to view more granular reporting on keywords.