Why the Quality Score Fluctuates

Why the quality score fluctuates at keywords level in the Campaign

[chriskriag]

I am new to google adwords, I found the quality score fluctuates a lot. I have keywords whose quality score was 8 and after 2 days it drops to 5. Why this is so?

And recently after running the campaign for 1.5 months I found few keywords with quality score of 5 suddenly jumps to 7. Why this is so?

Also please tel me is there anything like adgroup quality score or campaign level quality score?

[ACapetola]

CPC and/or Landing Page Quality

[ogletree]

Google starts out with QS based on historical data from other users plus your ad text and landing page quality. AFter a few days you build up your own reputation based on CTR. That is why it changes early on. You won't see that over the long run unless your making lots of changes.

Also don't forget the QS you see in adwords is just an average. The QS is determined separately for each search. Only exact match is close to accurate because phrase and broad because each term that triggers that term has its own separate QS that you can't see.