What is Quality Score?
Quality Score is Google's rating that is provided from1 to 10 Quality for each keyword in your account. Conventionally, new keywords get a null quality score. As you run your ads, based on your keywords performance data you may see changes in your quality score.
Three factors that regulate your quality score depends are detailed below:
1. Your expected clickthrough rate
2. The relevancy of your text ad.
3. Landing page and user experience along with AdWords historical account performance