Misconceptions of Keyword Density

Written by Brandon Schultz on Jan 12, 2012 3:19 pm

Bloggers and content marketers swear by it. I’ve heard it over and over that “you need to increase your keyword density” or “don’t go too high or it will considered spammy”. The idea just makes sense doesn’t it? I must admit on the surface without any careful consideration the thought of an ideal density makes sense. However this is just not the case. KD tools are not useless altogether. They might inform you that you haven’t used your keyword at all or you might be overdoing it.

Outside of that there is no real value in the measurement.

Dr. E. Garcia clarifies this principle in his paper The Keyword Density of Non-sense, and I highly recommend you read it. The flaws of considering density become glaringly obvious. You must take into account how many other pages use the keyword, how often they use it, and then normalize the equation to account for page size and repetition issues. In a nutshell term weight considers the overall database (search engine index) while keyword density looks only at your page. I hope this makes some sense.

Here is an example from Dr Garcia’s paper:

“If two documents, D1 and D2, consist of 1000 terms (l = 1000) and repeat a term 20 times (tf = 20), then a keyword density analyzer will tell you that for both documents KD = 20/1000 = 0.020 (or 2%) for that term. Identical values are obtained when tf = 10 and l = 500. Evidently, a keyword density analyzer does not establishes which document is more relevant. A density analysis or KD ratio tells us nothing about:

the relative distance between keywords in documents (proximity)
where in a document the terms occur (distribution)
the co-citation frequency between terms (co-occurrence)
the main theme, topic, and sub-topics (on-topic issues) of the documents”

Why then are there so many tools and SEO’s out there that measure keyword density?

For whatever reason misinformation has beat out mathematics and logic and people still believe in this nonexistent metric. Dishonest "SEO's" propagate this myth. The theory of keyword density is easy to understand and sounds believable. Anyone who hasn’t been otherwise informed should buy into the concept. Unfortunately it just isn’t true.

The only exceptions I can see are best explained by Rand Fishkin in a post on the topic.

“…I realized that term vector theory and term weights actually validate the positive results that people claim to get (me being one of them) when it comes to increasing keyword density/frequency. In less competitive markets and when going after long tail terms, the math actually makes sense. Consider that in these markets the document frequency doesn't fluctuate or grow at the rate of hyper-competitive markets. That said, changing the term frequency can have more of a dramatic impact, especially when considering competitor sites probably aren't well optimized on page and probably don't have great link strength.

If the environment doesn't change much, the effect of the number of total documents is little; it's the document frequency's stagnation that allows for a (seemingly) sustained advantage in this non-competitive market. So, if you're in such a market, by all means, fiddle with your keyword density/frequency, you might see some serious results through improving your term weight”

So what can we deduce from all of this information? Search engines have evolved to the point where they truly recognize good writing. A well written page needs the keyword only once or possibly not at all! Cramming keywords takes away from the readers experience as you will either insert them to the point of sounding robotic or delete valuable parts of your content to reach a certain “sweet spot”. The moral of the story is focus on good writing, not on the amount of times you can cram a keyword onto a page.

In closing, let’s hear it straight from the horse’s mouth. What does Google have to say about this?

Brandon Schultz

blog-instalation.com