Google Can’t Add! New Webmaster Tools Impressions Data Doesn’t Add Up


At first I was very excited about the new Webmaster Tools impression data released this past week. It seemed very promising. As any website owner I’m sure you would love to know how many impressions (how many times) your site shows up in the search results for a given keyword/search term. And as a SEO services provider it sounded like a dream come true.

Although it would seem like this would be simple to get the data correct and you would think Google would make sure its telling you the correct data at risk of being called out on it, but I think someone at the Googleplex has got a stuck down 7 key on their adding machine.

Surprisingly or not so surprisingly, the data just does not add up with the data you find in the Adwords Keyword Tool. I ran a little study on a few websites of mine and others before coming to this conclusion. I wish it were not so but the data speaks for itself.

Here are my findings from my personal running log website. A great site by the way, if you’re looking for a free easy way to track running workouts.

Keyword Webmaster Tools Impressions Adwords Tool (exact global search)
online running log 260 590
free running log 91 260
running logs free 36 170

Some notes on how I conducted this study:
My website remained in on the first page of Google during the entire past 30 days from which the data was gathered by Google’s Webmaster Tools. I also did not show up on any other search page during this time - just on page 1 of Google. So my results in theory should be very accurate. Then when using the Adwords Tool I made sure the Search Match was set to Exact and I used the Global Monthly Search Volume.

Now I went into this knowing that the search volume from the Adwords Tool is an average from the past several months so I take that into account when I look at the data from each. But even if you’re thinking with that the data just does not add up. I can see if the data was close then there would not be much for alarm but the data is not even close - it’s off by 100s.

So my next logical thing to do was check out another website’s data on this. I figured well let’s do someone with a more higher volume keyword that way we can also see my results are just an oddity or something.

I chose to use the data Aaron Wall from posted on his site when he reviewed this new Webmaster Tools impression data. Granted I don’t have access to his account I could see his 3 top keywords and their impressions data from his image that he posted on his website. But we also have to take into account (which was different than my website), his website is getting impressions on more than just the 1st page of Google (thus some duplicate impressions). So his impression results should be just a little higher than the Adwords Tool data.

Here are his results:

Keyword Webmaster Tools Impressions Adwords Tool (exact global search)
seo 74,000 1,000,000
seo book 5,400 9,900
seobook 4,400 5,400

As you can see again the data is just completely off. The Webmaster Tools data just does not come close to the Adwords Tool data. It’s off by many 1000s.

So what’s my conclusion…? Well I think that the webmaster tools data is more accurate than the Adwords data - or so it seems. I mean it would seem to reason it would be easier for Google to display more accurate data for your website impressions rather than make some calculations based on searches - such as the Adwords data. But I think I might be wrong again! Possibly neither data could be accurate.

I decided to take this study one more step further. Let’s look at my clickthrough data on Webmaster Tools verse my Google Analytics data. Now in theory these should be the same - the number of clickthroughs are the same as the number of unique visits from that keyword in my Anlaytics data.

Here is what I found:

Keyword Webmaster Tools Visits Analytics Visits
online running log 16 31
free running log 28 89
running logs free 5 31

Shocking! That data does not match up again. So now do I really trust Google Analytics or is it just that the Webmaster Tools data is just plan wrong. I choose to trust my Google Anlaytics data since I have test it in the past verse other visitor tracking software and they seemed to match up.

So that means the Webmaster Tools data is just plan wrong but what do we do? I don’t know that there is much we can do, possibly inform Matt Cutts or submit a post on the Google Help forum but I don’t know how much Good that will do. I image we will only get a response back saying …yes it’s no accurate… Well we know that, so all we can do really is move on and use the data with a grain of salt.

The data is still useful. It’s just like the old green bars in the Adwords tool before it gave you search volume numbers. You can use the data to give you a general measure of how well that keyword does against your percent clickthrough rate. Knowing that actually can help you make better decisions on which keywords you should focus more time on optimizing your website for. Aaron Wall was also kind enough to point this out too using his own data. Thank you Aaron.

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My testing gave the same results as you, Sean.

For a search term with 320 exact searches per month, which my client ranks 1st for, Webmaster Tools only showed 36 impression for the entire month and less than <10 click throughs.

My attitude with low search volume keywords has always been to keep a close eye on how many visitors they deliver as Google Adwords can not be relied upon to deliver accurate information!

One way to look at it is we have now have two useful, but imprecise tools (Google Adwords and Webmaster Tools) instead of one! ;)

SEOsean says:

Hi Anthony,
Yes you’re right the 2 useful but imprecise tools are better than one. At least we can bounce the data off each to get some sort of idea - just wishing one of them was actually accurate.
Thanks for letting me know about your results too.
- Sean

TraiaN says:

1. What you need to know and understand is that AdWords Keyword Tool is not returning the searches(impressions) done on only
2. Not 100% of the searchers will click on the first result
3. You need to take into account how the data for the tool is collected.

Considering the above, GA, AdWords and Webmaster Tools data will never match identically, but they will be close. Cheers.

PS: try to filter the analytics

SEOsean says:

Great reply TraiaN! You’re right, I didn’t take into account the Adwords Keyword Tool is also returning searches from Google’s network not just Google (don’t know why I didn’t think about that). Although, just as you said it still won’t match but even with that I am glad that at least these tools will give us a good indicator as to the data we are looking for. Thanks again for spotting that. - Sean

Andy says:

GWT is absolute uniques whether looked at for impressions or clicks.

If someone uses a term as a navigational query multiple times in a month, such as SEO book, you can be damn sure the numbers will be different.

The differences between seo book and seobook are great as well, as most queries for seobook will be navigational, whereas seo book would be maybe split 60/30 - the numbers add up.

The stats are real numbers, Google isn’t making them up.

I think you should not use “Adwords Tool (exact global search)” as you do in your second table but “Adwords Tool (exact local search)”
Iam in a hurry so i cannot give you that numbers right now but that should lower that Adwords tool numbers….

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