google keyword research tools - data comparison

One of the most important aspects of setting up a SEO or SEM campaign is identifying which keywords you are going to target. This is always a juggling act trying to find the phrases that are the most searched for, the most relevant and most likely to convert.

There are several tools that Google provides that can help with this process, namely Google’s Keyword tool and the Google Traffic Estimator. As a research-lead consulting organisation, we have decided to carry out a study to understand how accurate these sort of tools are, as well as document some of the inherent data limitations.

There now exists new Google Webmaster Tools functionality that shows impression and click through rates for organic search. After a bit of digging into this data, we were able to examine whether the tools complement or contradict each other.

We looked at three different keywords that give us a view of some different types of consumer searches.

Please note:

  • All figures were derived using the ‘exact match’ data provided by each of the tools.
  • Date ranges were almost all the same, Webmaster tools data was a couple of days out due to the limited time range this gives you, but deemed “close enough” for a rough comparison.
  • The site examined had a number of first position rankings for all phrases under examination, so we can be sure the impression number from webmaster tools is the most reliable possible.

google keyword traffic estimator webmaster tools data

We can see that all of these tools are presenting quite different numbers. While the External Keyword tool appears to be massively overestimating traffic, Traffic Estimator seems to be doing the opposite. This is especially surprising since they are supposedly driven by the same data. The positive news is that all of these seem to follow similar trends, and whilst the data does not line up exactly, the tools do give us a good relative indicator of what is being searched for.

keyword estimator tool google webmaster tools graph

What About Search Trend Tools?

Three major Google search analysis tools that provide trend-based data areGoogle TrendsGoogle Insights and the Google Keyword tool. We wanted to have a look at whether these lined up.

Looking at a “generic 1 word key phrase” and superimposing the graphs for each tool over each other, we can see that Google Trends (the red line), Google Insights (the blue line), and the Keyword Tool (the green bars) all correspond quite well, showing dips and peaks at the same times during the year.

google trends insights keyword tool comparison


You can’t use any one of these tools with absolute certainty. And no amount of data from last month will ever be able to tell you exactly what to expect next month.  What these tools are great for, however, is giving you an idea of what phrases and (product-) areas to focus on first. Common sense, knowledge of common consumer search patterns and understanding how the tools work (as well as the limitations) will help you find the best phrases possible for your site. And don’t forget to factor in Google Analytics keyword conversion data!