The analysis is actually not as innovative as the SEOS worldwide treat the topic. The origins of the analysis go back to the seventies, even though they naturally were not drawn for search engines or other rankings. However the formula and the calculation of terms on which the analysis is based dates back to the seventies. This information only mentioned incidentally. It is primarily all about understanding and clarifying the abbreviation, what is hidden behind the six letters:
Within Document Frequency – WDF
In words, this section describes nothing but the term weighting within a document. In turn the term in this case stands for the keyword which appears in a certain frequency in the text. This principle could represent the customary keyword density, however, WDF at the same time operates with a correction value which then allows for a uniform reference to result. In addition WDF is limited by the
Inverse Document Frequency – IDF
This area of the analysis does not only concentrate on one single document but refers the weighting of a certain term in the entire site. If, for instance in a blog only one single contribution on the site deals with photo albums the word “Garden chair” is important for the analysis – after all it is only mentioned in one single text on the site. However, if a term goes through the whole text, it is not interesting for the analysis as most probably not only one keyword is concerned.
If a text has an own DNA, the WDF*IDF analysis will reveal it. The latter of course only functions in a figurative sense, however the practical technique offers the possibility to reveal how well a certain word reflects the contents of a text. As already indicated in the example above, a word such as “and” will hardly point towards a relative content. The conjunction is found in every text and has absolutely no value to offer – other than to connect clauses and sentences. The word “garden chair” on the other hand already has a value and provides the opportunity to clearly localise search results.