One bad apple spoil the cart in the end.

There is adgroup QS, Campaign QS, and also Account QS. QS = Quality Score.

And all of these QS are connected with each other. I mean these are not independant actually in means of QS.

If you find something going very wrong in one adgroup (in one campaign) you should fix it. Otherwise your Google Adwords account may have cancer in the course of time. Like the human being.

Take care of your Google Adwords account as your dear pet or dear child )


Source:
http://www.911seosem.com/indexeng.html

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