[Tutorial] Keyword Density in 2014

Keyword Density in 2014

What does Google say about Keyword Density?

They advise against "Loading pages with irrelevant words" (aka keyword stuffing).

Often these keywords appear in a list or group, or out of context (not as natural prose).

[Source:https://support.google.com/webmasters/answer/66358]

In 2011 Matt C***s explained that keyword value is measured on a normative distribution curve; mention a word too few or too many times and it won't register. AKA there is an optimum density value!
[Source: http://www.youtube.com/watch?v=Rk4qgQdp2UA]

At the end of 2013, the Hummingbird Update placed emphasis on "Conversational Search", i.e. extracting meaning from a whole sentence, not just a few words. So how does that affect keyword density in 2014?

What do the SERPs show us?

Let's look at some of the top-ranking sites for the popular term "payday loans". This is a good phrase to test out because Google has already applied extra spam filters to the niche.
[Source: http://searchengineland.com/google-pay-day-loan-algorithm-google-search-algorithm-update-to-target-spammy-queries-162941]

Google.com Top 5 Results for "payday loans" (note: I am in the UK so results may differ)

#1 Repeats 36, Word Count 4033, Density 1.69%
#2 Repeats 97, Word Count 3632, Density 5.41%
#3 Repeats 15, Word Count 1689, Density 1.78%
#4 Repeats 15, Word Count 1474, Density 2.04%
#5 Repeats 66, Word Count 11,771, Density 1.12%

Result #2 stands out with a keyword density of over 5%.

The above figures take into account TEXT DENSITY. 

I'll crunch the numbers again but this time taking into account all content (text, alt tags, links, meta data etc)

#1 Density 2.36%
#2 Density 3.25%
#3 Density 2.69%
#4 Density 1.57%
#5 Density 1.35%

Now Result #2 has a more reasonable keyword density of 3.25%

Tentative conclusion: Google evaluates total keyword density over just text density.

Based on this tiny sample, a total density between 2 and 3% seems preferable.

Now onto a completely different niche:

Google.com Top 6 Results for "learn to swim"

Total keyword density

#1 Density 3.28%
#2 Density 0.24%
#3 Density 0.04%
#4 Density 0%
#5 Density 0%
#6 Density 0.73%

Aside from result #1 (a YouTube video) all pages have a total keyword density well below 1%, and two pages never mention the phrase at all.

Why is the keyword density so low?

While the density for the exact phrase "learn to swim" is low or non-existent, the Hummingbird effect can be seen at work here.
[Source: http://www.searchenginepeople.com/blog/detailed-analysis-of-semantic-search-and-its-role-in-hummingbird-algorithm.html]

Results are automatically picked (and highlighted) for the phrase "learning to swim" too:

Results also show for the word "swimming".

The most commonly found words on the top-ranking pages are:

swimming, water, pool, training, swimmer, swim

and phrases:

how to swim, in the pool, in the water, learned to swim

Between the Top 6 results, the phrases "in the water" and "how to swim" occurred much more frequently than the exact phrase "learn to swim". 

This is evidence of Latent Semantic Indexing (LSI) at work. 

How does Latent Semantic Indexing work?

A massive volume of texts are scanned and a mathematical algorithm then calculates patterns and trends between words. This is how we know interesting facts like "the" is the most used word in the English language.

Google use LSI as one of their many search algorithms. Using the above example, Google's LSI formula has determined that articles about "learn to swim" must also explain how to get "in the water" and teach us "how to swim". 

It's a form of artificial intelligence that looks set to get more sophisticated based on the $Billions Google is spending on acquiring AI technology. [Source:http://techcrunch.com/2014/01/26/google-deepmind/]

LSI Further Reading: http://www.seobook.com/lsi/lsa_definition.htm

What does this mean for Keyword Density in 2014?

Here are some informed suggestions for creating top-ranking content and good on-page SEO in 2014:

TIP #1:Evaluate total keyword density (not just visible text).

HOW? Paste your site in one of the tools given below in the Resources list. 

WHAT PERCENTAGE? 1-3% still seems like a safe bet, but perform some competition analysis to double-check. Ultimately, it will depend on your keyword because the principles of LSI determine that your optimum keyword density is related to the density of other sites that use your keyword!

TIP #2:Use long sentences, especially when including your "keyword".

HOW? See the difference:

BAD: Used cars are cheaper than new cars. People on a budget can benefit from used cars.

GOOD: There are over 250 million used cars registered in the US, making the second-hand car market one of the largest in the country.

TIP #3:Find and include terms related to your niche. 

HOW? There is a link to a free LSI generator tool in the Resources list. It also pays to analyse (again, with the tools given below) the top 5-10 results manually for extra ideas. 

Resources:

Calculate text density using SEOquake (firefox plugin):

http://www.seoquake.com/

Calculate total keyword density:

http://tools.seobook.com/general/keyword-density/

LSI Generator:

http://lsikeywords.com/