What does a high Quality Score indicate?
Your ad and landing page are relevant and useful to a viewer.
Your bid is high enough to have your ad displayed.
You have been an AdWords user for a long time.
Your ad relevance and landing page are below average.
Quality Score is intended to give you a general sense of the quality of your ads. Three factors determine your Quality Score:
- Expected clickthrough rate
- Ad relevance
- Landing page experience
So, having a high Quality Score means that our systems think your ad and landing page are relevant and useful to someone looking at your ad.
Read more here: https://support.google.com/adwords/answer/7050591