How important Is Click Through Rate In Google’s Quality Score Formula?

A question often posed by marketers is, “What is the relative importance of different factors Google uses to determine quality score (QS)?”. Some of the factors mentioned on the AdWords blog are:

  • Click through rate of the keyword and the matched ad
  • Account history
  • Landing page quality
  • Keyword/Ad Group relevance

The question for an advertiser then becomes, “What factor should be the primary focus when trying to improve my quality score?.” The answer is overwhelmingly the click through rate (CTR).

For the analysis, we looked at several Google accounts and plotted quality score vs. CTR. A typical plot for a large account with 500,000+ keywords looked like this:

CTR vs. Quality Score

Several interesting patterns show up:

  • Quality scores from 1 to 8 are very well explained by CTR. Notice how the linear regression (line fit) aligns so well with the observed pattern. The R squared of 72% of the trend is explained by CTR alone.
  • There is a sudden jump at a quality score of 8.
  • While CTR does not explain the jump between 9 and 10, there is a huge jump in CTR between 8 and the higher quality scores.

But there is more to it. Some quality scores appear more frequently than the others. We found in our analysis of millions of keywords that quality scores of 8 and 9 are very rare. Here is a typical example for a Google account. It appears that the quality scores of 8 and 9 are “transition” regions. While a linear trend explains the QS-CTR connection until the score of 7, keywords with QS of 9 and 10 require a very high quality score compare to the rest.

Percentage of Keywords vs. Quality Score

We found this pattern across the board, in all verticals.

The takeaway is that when looking to improve quality score, first seek to improve your CTRs. This will have the biggest impact, by far. Do not worry if you see very few keywords at a quality score of 8 or 9. These scores are rare and do not appear to have a direct connection with CTR related factors. There is not much you can do to get these scores. In fact, it likely has something to do with the way Google’s Quality Score algorithm works. Once you have the CTR piece of puzzle solved, work on the other factors (such as landing page quality, ad copy relevance and campaign structure) to improve your quality score. And don’t waste your time fretting about getting the highest score.

Opinions expressed in the article are those of the guest author and not necessarily Search Engine Land.

Related Topics: Channel: Analytics | Search & Analytics


About The Author: is Director, Business Analytics at Adobe. He leads a global team that manages the performance of over $2 BN dollars of ad spend on search, social and display media at Adobe.

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  • Maggie@losasso

    In your experience what is the best way to optimize campaigns/keywords for a better CTR rate? In my experience, I try to raise the bid and edit the ads through A/B Testing for the most effective ad combination. This generally works well, but I am open to any ideas other people may have as well.

  • sidshah

    There are two ways you can do this Maggie. for keywords that are already bid to high positions (page 1 for instance) you can do it by A/B ad copy testing. Once you have enough data to make a conclusion dump the poorer CTR ad immediately. How also check to see if both ads have similar ROIs. If the higher CTR ads are actually converting poorly, then you might be attracting a lot of unqualified traffic. But all else being the same you want to shut off the poorer CTR ad, so that your QS can improve even faster.

    The other way you can improve QS esp. on the tail is to expose these keywords. If they havent seen page 1 or 2 , you can take a small set of them and bid them up for a few days so they have the opportunity to get clicks. Just be careful because you dont want to blow your budget on a set of bad keywords. I recommend increasing bids on your underexposed keywords by 20% every 3-4 days until the bid is at the average CPC of the campaign.

  • absem_limited

    I agree with Siddharth Shah. Although I have not done such an indepth analysis to find a correlation, I have done some tests around other things to improve the quality score. Just wanted to share a link with the readers from my blog is possible:

    Hope this helps.

    Thank You


  • yesweet

    I don’t know how to say, but it seems that Google had announced that they get rid of CTR out of evaluing of QS, cause the position certainly influences the CTR…

    For more detail please find


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