In Google Ads, quality score is available only at the keyword level. Tenscores computes those keyword-level quality scores and averages them out to provide them at the ad group, campaign and account level.
The averages aren't simple averages, they are impression-weighted averages. Meaning that keywords with more impressions have more importance in calculating the average quality scores.
Example
Lets take 2 keywords, one with a 4/10 quality score and another with a 10/10, both with different number of impressions:
Keyword #1
Quality scores:4/10
Impressions: 1,000
Keyword #2
Quality score: 10/10
Impressions: 10
Regular average
(4 + 10) / 2 = 7
A regular average quality score for this ad group would be 7/10, but it would be misleading as the first keyword is more important due to the volume of its impressions, and the second is almost insignificant even though it has a perfect score. That's why we use the weighted average computation below.
Weighted average
The weights:
Keyword #1: 1,000/1,010 = 0.99
Keyword #2: 10/1,010 = 0.009
The calculation:
(4*0.99 + 10*0.009) = 4.5
The impression weighted quality score for this ad group would thus be 4.5/10 .
Why is this useful?
This gives you an accurate overview of the overall health of your account, and provides a reason to understand fluctuations that are due to pausing or activating new campaigns or ad groups.