Q: How do you feel about using Google Trends as a tool for search term relevance and popularity?

A: Google Trends is a tool that allows you to compare the popularity for up to five keywords or phrases over a period of time. I think it’s a great idea, and I have played around with it during keyword reseach, but I haven’t yet found a way to make it useful in that way. There’s nothing wrong with Google Trends – it just isn’t trying to be a keyword research tool. It might seem premature to pick apart something that’s in early beta, because it may change at any time. But Google Trends is free, so I’m guessing that if you and I have thought of using it as a keyword research tool, then other folks are considering the same thing. Let’s see how it measures up.

The first thing to note is that, at this time, Google is only using a portion of its search results in the calculation of its trend data. So, it’s important not to put too much stock in the results you get.

Now, let’s look at some sample results. Here, I looked for a correlation between the words “halloween” and “candy” by entering the query: “Halloween, candy”:

My first impression is that Google Trends keeps too much important data hidden to be meaningful in keyword research. A keyword research tool has to give you some hard data so that you can make an educated guess about what’s worth your time and energy to target on your site. Google Trends displays a vague timeline, and gives you no indication of the number of searches that you’re looking at. The lowest point is labeled “0”, but what’s the top? 100? 100,000? Without that information I can’t act on what I see.

This is most confusing when you’re looking at two words with significantly different search volumes.  In my “Halloween, Candy” example, I see the spike I expect around the same time of every year displayed for the word “Halloween” but not for “candy.”  So I searched both words separately. The graph for “Halloween” looked about the same, but the graph for “candy” looked much different when viewed by itself. It was much easier to see separate peaks and valleys, presumably because the scale had been altered when this term was displayed on its own.

Another strike against Google Trends as a serious keyword research tool is that it doesn’t offer any keyword suggestions. For example, I queried: “Halloween, horror DVD”. Again, the spike for “Halloween” was clearly seen. But there was no corresponding spike for “horror dvd.” Because I’d already done keyword research elsewhere, I knew that the term “horror movie” is more popular than “horror dvd,” so I changed my search to “Halloween, horror movie.” There, I saw a nice correlation. Without built-in help from Google Trends, I had to rely on my own knowledge and prior research to find the significant trend.

And one more problem: Google Trends isn’t clear enough about how it’s filtering the terms you enter. Is it looking for exact matches of your terms? Is it returning data on broader terms that contain the phrase you entered? I played around by refining my query, for example, searching for variations on “emmy, red carpet”, using various configurations of quotes and plurals, and I was able to get different results.  Google Trends also offers some helpful advice on advanced functionality, which includes some non-standard operators, such as the vertical bar. This is fun, but still I have the distinct feeling that I’m playing “guess the algorithm.” Again, there’s nothing wrong with that; it just isn’t great for serious keyword research!

It remains to be seen whether Google will continue its slow takeover of the world by making Google Trends into a robust free keyword research tool. But what can you use it for now? Well, Google Trends could be useful when you’re trying to nail down the timeframe of a seasonal word (i.e. should I start my Christmas promotion in October or December?). At this point in time, I think the best use of Google Trends for SEO purposes – other than fun – is to confirm a trend that you were pretty sure about in the first place.