What does WDF*IDF mean?
WDF*IDF is used to assess the occurrence of a keyword in relation to all other pages that rank with this keyword. This also includes certain terms on a page that belong to the keyword. Such an analysis is not only about the keyword density, but about all text content of the examined page in comparison with other pages.
Within Document Frequency (WDF)
WDF is an abbreviation for “Within Document Frequency” and represents the relative frequency of a keyword or term in a specific text document. This checks the relationship between this frequency and all other keywords from the same document. Unlike the keyword density, a logarithm is added here. The WDF formula is as follows:
The numerator in this formula represents the frequency of the term “i” in the document “j”.
The denominator shows the number of all terms in document “j”.
Inverse Document Frequency (IDF)
In contrast to WDF, IDF is the abbreviation for “Inverse Document Frequency”. The frequency of a keyword in a specific text document is set in relation to the frequency of the same keyword in all other known documents.
As with WDF, a logarithm is also included in the formula here:
In this formula, the counter represents the number of all documents in the document corpus.
The denominator, on the other hand, contains the number of all documents in which the term “i” appears.
Once both formulas, WDF and IDF, have been determined, they are multiplied together. This shows the relative term weighting of a text document in relation to all documents in the corpus that contain the same keyword.
What does WDF*IDF mean for SEO?
In the field of search engine optimization, a WDF*IDF analysis is used to calculate the relevance of your own content in relation to the content of other websites. The aim is therefore to find out which keywords and their associated terms can be classified as relevant in a text. The ranking factor here is the relevance of texts to a specific search term. As soon as the user receives a search result for their search query and does not consider it relevant, it will probably no longer be displayed in the search engine they are using.
There are several common WDF*IDF tools to carry out an improvement after a WDF*IDF analysis. These tools then indicate which terms should be increased, reduced or added to the text. The aim of this process is to achieve an “average”. In practice, the term “average” is not used, as it could be misinterpreted. More appropriate are “comprehensive” or “holistic”. The more holistic a topic is in a document, the more likely it is to rank on Google.
Originally, keyword density was the most important factor in SEO texts. Accordingly, a keyword should appear as often as possible in a text, which increases the relevance of the text. The problem that arose from this was that the texts were not particularly user-friendly, as they were barely legible or difficult to read. Fortunately, these types of texts have been declared obsolete by Google’s Hummingbird update. Since then, this algorithm has been much better at recognizing the user’s search query and the content of a web document.
On the one hand, the texts are now more readable, but it is now also much more difficult to write relevant texts that also stand out from the competition. The best ranked websites should be analyzed with the WDF*IDF formula for the ratio of terms contained. This content is then compared with your own website.
In general, a WDF*IDF analysis is used for every on-page optimization. The ranking-enhancing effects can be seen over a longer period of time.
Areas of application for the WDF*IDF analysis
The WDF*IDF tools already mentioned can be used for a wide variety of areas. The following three are the most important areas where optimization is possible through analysis.
1. keyword research
The WDF*IDF analysis makes it possible to identify particularly relevant keywords that are used by a large number of websites on a specific topic.
2. competitor analysis
The WDF*IDF analysis can be used to identify particularly relevant keywords that are used by several websites on the same topic.
3. optimization of existing texts
A website’s own WDF*IDF values can also be checked. By analyzing your own content, new texts with relevant terms can be constantly added and improved.
Despite all this, the focus should not be too much on analysis, as the texts should still be easy to read and user-friendly. Not only the keywords, but also many other factors influence the ranking position on Google. It is therefore important to write the texts for the user and still take all SEO factors into account as far as possible.