Keyword Density and Search Engine Results Position are important considerations when writing an article that will be published on your website. A keyword is the main idea of the article in question, its subject. Example: if I am writing an article about The Dark Knight Rises, that is the article’s main idea, its primary keyword. Keywords and their density within your article are one of the factors that effect its results position in search engines (SERP). I previously spoke about the use of keywords here: Keyword Placement for High SERPs (Search Engine Result Positions) and here: Proper Keywords and Tags to Maximize Google AdSense Ads.
Whether you are conscience of this factor or not, when you are writing an article on a subject, you are employing the use of keywords. In regards to their density in an article, keyword “density is the percentage of times a keyword or phrase appears on a web page compared to the total number of words on the page.”
Though not as imporatant as it once was for search engine optimization, keyword density is still something that should be kept in mind when writing an article. “In the context of search engine optimization keyword density can be used as a factor in determining whether a web page is relevant to a specified keyword or keyword phrase. In the late 1990s, which was the early days of search engines, keyword density was an important factor in how a page was ranked. However, as webmasters discovered this and the implementation of optimum keyword density became widespread, it became a minor factor in the rankings.”
Minor but still present, still a factor in how your article is ranked in a search engine.
Though using keywords in your article is advantageous, do not be obvious and over do it. The “overuse of keywords, a practice called keyword stuffing, will cause a web page to be penalized. Many SEO experts consider the optimum keyword density to be 1 to 3 percent. Using a keyword more than that could be considered search spam.”
How do you know if you are over doing it or not? Use math and throw the keyword and the number of words in your finished article into a keyword density equation.
The formula to calculate your keyword density on a web page for SEO purposes is, where Nkr is how many times you repeated a specific keyword and Tkn the total words in the analyzed text. This will result in a keyword density value. When calculating keyword density, be sure to ignore html tags and other embedded tags which will not actually appear in the text of the page once it is published.
When calculating the density of a keyword phrase, the formula would be , where Nwp is the number of words in the phrase. So, for example, for a page about search engine optimization where that phrase is used four times and there are four hundred words on the page, the keyword phrase density is (4*3/400)*100 or 3 percent.
However, from a purely mathematical viewpoint, one cannot ignore the fact that the original concept of keyword density refers to the frequency (Nkr) of appearance of a particular keyword in a dissertation. Thus, a “keyword” consisting of multiple terms, e.g. “blue suede shoes” should be considered an entity in itself. It is the frequency of the phrase “blue suede shoes” within a dissertation that drives the key(phrase) density. Thus it is “more” mathematically correct for a “keyphrase” to be calculated just like the original calculation, but considering the word group, “blue suede shoes,” as a single appearance, not three. Thus:
Density = ( Nkr / Tkn ) * 100.
Furthermore, under closer inspection, one can see that these ‘keywords’ (kr) that actually consist of several words, artificially inflate the total word count of the dissertation. Therefore, it could be argued that the purest mathematical representation should adjust the total word count (Tkn) lower by removing the excess key(phrase) word counts from the total. Thus:
Density = ( Nkr / ( Tkn -( Nkr * ( Nwp-1 ) ) ) ) * 100. where Nwp = the number of terms in the keyphrase.
This general formula allows that the total word count will be unaffected if the key(phrase) is indeed a single term, so it acts as the original formula.
Or just do not over do it with keywords in your articles. A great plugin that lets you see the number of keywords in your post before and after you publish it is WordPress SEO, written about here: 4 WordPress Plugins: SEO, Google Analytics, Image Resize, Contact Form.
Use keywords in your articles but watch how many times you use them.