Understanding how Google organizes search results is the first step to optimizing your page's visibility. Of Google's roughly 130,000 ranking factors, keyword density is a long-debated metric that has resurfaced with the recent algorithm document leak.
The leak suggests that keyword density likely has a big impact on a page's ranking in Google's SERPs.
But first, let’s talk about the fundamentals and why they’re important. Reliable and consistent search engine optimization applies key elements that are likely to lead to higher rankings. Focusing on the fundamentals is both efficient and effective.
In SEO circles, keyword density is called “term frequency.” Some call it “keyword stuffing.” Either way, the goal is to increase the on-page frequency of the keywords you want to rank for.
'skin care'
Consider a competitive term like “skincare.” Below are the top 5 ranking domains for “skincare” and the number of times the word appears in the HTML (in Chrome, go to View > Developer > View Source):
- Sephora.com – 762
- TheOutset.com – 165
- Fresh.com – 607
- CreamySkincare.com – 182
- Skinbetter.com – 596
The Outset and Creamy Skincare ranked in the top 5 despite relatively few keyword mentions, showing that there are many ways to rank a page. The other three suggest that there is a linear relationship between keyword density and ranking.
According to Search Engine Journal in 2019, when asked if keyword density was a ranking factor, Google spokesperson John Mueller responded, “It's a fairly old metric that has evolved quite a bit over the years. There are many other metrics out there.”
While Mueller acknowledges alternative metrics, he doesn’t deny that keyword density is a fundamental ranking factor.
Google may use a diversity of factors to identify and eliminate attempts to manipulate its search algorithms. In other words, keyword stuffing alone won't work on, say, an e-commerce product page. But keyword stuffing in combination with other factors will.
Main factors
Google's top 200 ranking metrics are reported daily by Top SEO Factors, developed by Ted Kubaitis, who also creates an SEO analysis tool called Cora.
As of June 17, 2024, Kvaitis' top three factors are:
- Number of unique latent semantic keywords used [i.e., words related to the target],
- Number of distinct entities used [i.e., an identifiable thing in a database],
- A domain can be .com, .net, or .org.
The top two are likely fundamental factors, while the third is likely due to the number of top-level domains that use .com, .net, or .org.
“Term Frequency” is #33 on the list, down 18 places in the past 30 days, but still #33 out of 130,000 words.
A recently leaked Google document contains a lot of mentions of “term frequency.” Read it for yourself on the page created by Dixon Jones, a developer who created a tool to research entities related to your target keywords.
The Google leak is only documentation, not source code. Many of the notes are out of date and contain undefined words, ratios, and calculations. So all we can say for sure is that Google is using, has used, or considers these elements. At some point.
Still, based on the shared testing and knowledge of the SEO community, this leak reinforces many practices that are already in place.
For example, a search for “term frequency” on Dixon's site returns six results that reference “Tf,” which the document defines as “term frequency.” These references indicate that keyword density is fundamental to search engine optimization, especially at the beginning of a document, but “the beginning” is not defined.
Additionally, the leak suggests that Google does consider the ratio between a keyword and all other pages on the web that use that keyword, but calculating this for every search seems prohibitively expensive, whereas keyword density on a single page is not.
It seems difficult, if not impossible, for an algorithm to determine the topical relevance of a page without at least taking into account keyword density. What could be a replacement for a term like “computer” without a certain number of uses of that term or its synonyms?
Wikipedia, which ranks #1 for “computer”, has the word included 1,354 times in its page's HTML, which is also visible to everyone.
Remember that keyword density is just one factor among many – overusing it may not help you rank, but when combined with other key factors it is more likely to help pages with ecommerce products rank.