Yesterday, one of my readers left a comment in response to Cash For Content and the blueprint that comes with it. Abi had some very good questions about keyword density:
I have to agree that the toolbox is really a very good blueprint.. but i have a question.
does the kw density thing still work?i mean i have heard lot of people talking about the importance of LSI and that KW density will have a negative effect and all..
what is your opinion? does KW density of 3-5% still work?
Let me see if I can answer these questions.
What Is Keyword Density?
The term keyword density, or more properly keyphrase density, is a simple measure of how many times a given keyword/keyphrase appears in a text in relation to the total number of words/phrases in that text. It’s usually expressed as a percentage. Consider this text:
This is a silly little text that I made up. This is a dumb example. But this is enough to show what I mean.
In this example there are 24 words. The keyword “this” appears 3 times in the text, giving it a keyword density of 3/24 = 12.5%. On the other hand, there are also 23 two-word phrases (phrases of consecutive words), with “this is” also showing up twice, giving it a density of 3/23 = 13.04%. You could also measure 3-word phrases, 4-word phrases, etc.
Calculating keyword density for a web page is very simple: take the content between the <body> and </body> tags and strip out all comments, HTML tags and punctuation to be left with a set of individual words, then calculate the appropriate density for the size of phrase you want. Any programmer can write code to do this, though doing it efficiently and quickly for large amounts of text is non-trivial.
Why We Care About Keyword Density
You’re probably wondering why keyword density is important. It’s because it’s an easy (but not always accurate) way for a computer to determine the topic of a given text.
Think about it. If you’re writing an article about golf clubs, for example, the words “golf” and “club” as well as the phrase “golf club” (and plural variants of these) will be mentioned several times. It’s only natural:
The best golf club is one that is the right length for your height. The club must not be too long or too short; you must be able to grip it comfortably at the top without only minimal bending at the waist. This is why golf clubs come with different shaft lengths and why avid golfers buy clubs that are too long and get them shortened to the right length. A well-fitted club makes an incredible difference in the quality of your stroke.
The paragraph above is total poppycock, I have no clue if it’s right or not, but I wrote it naturally and you can see that “golf”, “club” and “golf club” did indeed appear several times in the text. I could have gone overboard and said “club” instead of “it” in a couple of spots, but that wouldn’t seem natural to me. (I’ve talked about excessive use of keywords before in Human Search Engine Optimization, I suggest you read that article for a more thorough discussion.)
So when computer scientists first tried to write algorithms that could decipher what a text was about, they noticed that in many cases a frequency count — which is what keyword density is — was an easy way to do basic topic determination. But it’s only a rough approximation. The more florid the writer, for example, the more likely they are to use synonyms and idiomatic phrases that don’t get caught by a simple keyword density test. This is where more sophisticated algorithms like latent semantic indexing come into play. But they’re much harder to implement.
Spammers and Keyword Stuffing
Early on, search engines used keyword density as one measurement to determine how relevant a page was to a given keyword. Of course, spammers quickly latched on to this and started creating pages stuffed with keywords they wanted to target. To fight back, then, the search engines placed a limit on the keyword density they expected from a legitimate page. That’s where the “3-5%” rule you see mentioned many places comes from: too low and the search engine may think the page is about something else, too high and they think the page is spamming. But these are just guidelines and of course nowdays there are many more factors that are used to determine how well a page ranks, such as the anchor text of links pointing to the page, keywords in title and URL, what other related pages talk about, etc. Note that the AdSense algorithms use many of the same rules (plug: buy a copy of Uncommon AdSense and you get a free detailed report on the AdSense patent that explains all of this) to determine which ads to serve for a given page, which is why optimizing a page for AdSense is very nearly the same as optimizing it for the search engines.
Putting The Cart Before The Horse
Focusing too much on keyword density, however, is putting the cart before the horse. As long as you write natural-sounding content (i.e. written for humans) and pay attention to a few basic SEO rules (keyword in title, good URLs, one-way links back to the page, etc.) then you don’t need to worry about keyword density. Good keyword density is just a byproduct of good writing, and the algorithms are sophisticated enough these days to figure out what you’re writing about without having to resort to extreme measures.
My advice is to write without worrying about keyword density. When you’re done writing, pass your text through a keyword density analyzer (for short online texts you can use this free keyword density tool) and see what your most prominent terms are. You may want to tweak things a bit, especially if you’re focusing on some long-tail phrases, but at this point it’s more of an editing task than a writing task, and you still want the end result to read well. Now, things get tricky when you’re dealing with images and very little text, in which case different rules apply, but for text content writing good, quality material is still your best bet.
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Eric Giguere is the author of Uncommon AdSense and the award-nominated (that just means it lost!) blog Make Easy Money with Google and AdSense.
Wow Eric, you made me famous
and this post solves most of my doubts, thanks.
But would a quality article rank better in search engines with a better keyword density? this is in concern to bum marketing.
It’s hard to answer these questions, to be honest, because pages don’t live in a vacuum. The answer depends on what the other pages you’re competing against are like and what kind of search engine optimization they’ve done. Everything else being equal, a higher keyword density is better, yes. But things are rarely (never!) equal. A low-density page can easily outrank a high-density page if there are more and/or better links to it, for example. Write good content, then edit it with basic SEO principles in mind. That’s the best way to get going. Once you have a page indexed, you can compare it to its competition and start tweaking things.
thanks a lot.. exactly what i wanted to expect..
if you read a few guides of ewen chia, you can notice he makes some pretty interesting point on article marketing..
primary keyword density: 3-8% [8% is way too much thou]
two additional kws density: 1.5-3%
kinda like using LSI
thanks eric, you made my day with the density tool.. now i see why my competitors rank better than me
and would like to tell you, i am a big fan of your blog and really enjoyed the adsense arbitrage case study..
i hope you make another case study on another money making model..
In a word, NO. See my post Five Outdated SEO Myths. Wil Reynolds’ speech at Affiliate Summit explains it.
Nice post, Michael, and I think it definitely helps explain the state of the art these days.
Personally, the only time I ever worry about keyword density when I write something is when I’m trying to match an AdWords ad to a landing page, in which case I want the landing page to reference the keyphrase I’m using several times to get me lower advertising costs. Or if I’m trying to fix the occasional mistargeted ad. But generally I don’t worry about it and things work out anyhow.
Does Keyword Density Matter? Your post came up on my horizon and I have a couple of reads for you; http://www.seo-blog.com/keyword-density.php and http://www.seo-blog.com/latent-semantic-index-lsi-myth.php
I hope they help.
- Michael
Those are good articles, Michel, especially the one about LSI. Again, I think we all agree on the general principle here: write well for human readers and things will mostly work out.
I have a totally different definition of keyword density and wrote three articles about it.
http://heartdaughter.com/blogs/elijah/index.php/2007/06/27/192/
http://heartdaughter.com/blogs/elijah/index.php/2007/07/02/224/
http://heartdaughter.com/blogs/elijah/index.php/2007/07/12/278/
My method is giving me highranks in SERP
nada
part 4 in the series
SEO tips for Meta Description / Keyword Density, Blogskinny, and self hosted WordPress
http://heartdaughter.com/blogs/elijah/index.php/2007/07/23/328/
My method is giving me high ranking in SERP
nada