What is Google Quality Score?

January 21st, 2008 by Mike

It has always been known to everyone within the world of pay per click, but one thing that has really struck me this week while managing my client's accounts is just how much grey area surrounds quality score.

First let's look at a brief version of Google's explanation of Quality Score:

Quality Score is a dynamic variable assigned to each of your keywords. It's calculated using a variety of factors, and measures how relevant your keyword is to your ad text and to a user's search query.

Quality Score helps ensure that only the most relevant ads appear to users on Google and the Google Network. The AdWords system works best for everybody—advertisers, users, publishers and Google too—when the ads that we display match our users' needs as closely as possible. Relevant ads tend to earn more clicks, appear in a higher position and bring you the most success.

On three separate occasions this week, within three different accounts, I have discovered that keywords are being served with ads from different ad groups within the account. For example, I have an account for a company which sells both new and used cars. These are separated out into different campaigns within the account and split down for relevancy. I have then written ad text targeted to each individual ad group. I then performed a search for ‘used car’ and was served by the ad for ‘new car’ which is contained within a separate campaign.

So why does this happen?

As I understand it, the reason why this ad is being shown is because it is coming out on expanded match. The Google Algorithm is serving the ad that it believes is most relevant to the search query and also has the best quality score.

I would take you back to the Google explanation of quality score at the top of my article, which states ‘Quality Score helps ensure that only the most relevant ads appear to users on Google and the Google Network’ but how can searching for a ‘used car’ and being served by an ad for ‘new car’ be considered relevant. Answer is that it’s not!

So how do we stop this from happening?

Across your campaigns in an account you need to use your negatives wisely. If you don’t want a certain ad to appear for a certain keyword then make sure that the keyword is in as a negative. For example, we would put ‘used’ in as a negative on the ‘new car’ campaign.

The question needs to be asked, how can Google be allowing this to happen, when the whole basis of Quality score is for user’s to be able to select from the most relevant ads for their search query.

Should the algorithm be improved to build walls around separate ad groups so the ads written for specific ad groups can be the only ones served for keywords contained in that ad group?

Does the algorithm use any keyword matching between keywords and ad text or is this based solely on historical data for quality score?

This entry was posted on Monday, January 21st, 2008 at 6:10 pm . You can follow any responses to this entry through the RSS feed.

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