Is there any truth to this? I have over 100 ad groups that don't get impressions. can these ad groups hurt my QS?
Are you using the "common keyword grouping" method for those ad groups that aren't getting impressions?
Quality score pretty much related to the keywords inside your AdGroups. Each keyword has its own quality score under your AdGroups. Therefore having many many AdGroups doesn't cause lower quality score.
I would say not but, to answer fully, you would need to know the performance data of the words in those adgroups. If poorer (low QS, low CTR) than your average then they could damage your QS in the other groups, if better then they will help. However, you say they are getting no impressions at all. If so, then they cannot effect QS. Even if they are getting only a few impressions, i.e. a small percentage of your overall account impressions, it will have little effect either way. Incidentally, whether they are harming you or not there is little you can do about it short term - Google retain the data and use it as part of the QS calculation (Historic account performance). If they are getting some impressions and accumulating data that you think is damaging your overall performance then it would be best to pause or delete the groups. That way, although it will not have any immediate effect, the significance in the historic data will dwindle over time (although you will never be rid of it entirely!)
If you have over 100 ad groups with zero impressions why don't you just delete them? I'm on the fence if these will or won't be affecting your QS - but in any case if they're not working you may as well get rid of them - I think having a 'cluttered' account generally makes everything that little bit more difficult to manage anyway - I'd delete them
the ad groups will not hurt the QS.. the keywords and relevance to your ads will hurt the QS.. if you have adgroups with lot of keywords, you should split the relevant keywords and create ads targetted for those keywords to improve your QS.. also ensure the landing page has that keyword.. you should check for the keyword QS and remove / modify the ones which have a poor QS
I would say any keywords that get zero impressions don't have a + or a - effect on your QS. Only my view though, so it may not be gospel. With regards to just deleting them - I'd give them 2-3 months first and then delete them, if they still don't have any impressions after that time.
my first thought is, what are you bidding? my second thought is, what are your keyword QS's? i'm not sure how you can have 100 ad groups and zero impressions. the *number* of ad groups alone should have no bearing on performance. if you've set them up correctly, and bid a reasonable amount for your vertical, you should see impressions. if you think they're set up correctly, bid higher.
From my experience, many keywords and ads that don't get clicked don't effect my others. From what I see, each one seems to have their own quality score. But that would be good to test and find out for sure though. Would take a little money to test it.