Understanding the tdf*idf method to improve your SEO

Through our SEO Agency Optimize 360

on the theme : Technical SEO

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In a world where Search Engine Optimisation (SEO) is crucial to ensuring the visibility of a website and attracting visitors, it is essential to master the techniques for improving this key factor.

These include the tdf*idf method (term frequency-inverse document frequency) is an interesting approach to optimising the textual content of your pages, particularly in terms of weighting and information retrieval.

What is the tdf*idf?

To understand what tdf*idf is, we first need to break this formula down into its two components: term frequency (tf) and inverse document frequency (idf).

Term frequency (tf)

Term frequency is a measure that indicates the distribution of a word or expression in a given document.

More specifically, it calculates the number of hits of a term divided by the total number of words in the document.

This measure enables us to assess the relative importance of a word within a text, since the higher its frequency, the more likely it is to be representative of the subject being addressed.

The inverse of the document frequency (idf)

But while the frequency of a term indicates its importance in a particular document, it is also useful to take into account its rarity or community through all the documents in our database (for example, a set of articles or web pages). This is where the inverse of document frequency comes into play:

1. 1. Firstly, we calculate the document frequency (df), which corresponds to the number of documents containing a given term;
   2. The total number of documents is then divided by the document frequency (N/df);
   3. Finally, we take the logarithm to base 10 of the result obtained.

So the rarer a word is in the collection, the higher its idf will be and the more valuable it will be. This measure therefore makes it possible to penalise terms that are too commonThese include articles, prepositions, etc., which are not very informative and do not discriminate.

Combining the two measures: tdf*idf

Once we have calculated the tf and idf for each of the terms present in a document, we can then calculate their product to obtain the tdf*idf. This combined measure represents both the relative importance of a word in a specific text and its overall specificity:

• A common term in a document but rare in the collection will have a high tdf*idf, indicating great relevance to the content covered;
• A common term both in a document and in the collection will have a lower tdf*idf, as it will be less informative and discriminating;
• An uncommon termwhether common or rare, will also have a low tdf*idf, a sign of its low importance.

Concrete example of tdf*idf application

To illustrate the use of this method for SEO purposes, let's take the example of an article about electric cars. The terms "car" and "electric" are probably frequent in the text, which gives them a high tf. But if these words also appear frequently in other related articles, their tf will be lowered.

On the other hand, a word like "autonomy" could be less frequent but nevertheless specific to our document (in relation to the context). It would therefore have a higher tdf*idf, reflecting its informative nature and relevance to the subject. For this reason it is crucial to identify and use the most representative keywords to improve your site's SEO.

The role of tdf*idf in information retrieval and SEO

How search engines work

Search engines such as Google, Bing or Yahoo work in two key stages:

1. 1. Indexing, which involves receiving information from a website and then analysing and organising it;
   2. The user query, which triggers a search of the indexed data to select the relevant pages.

It is during this second stage that the tdf*idf comes into play as a relevance criterionwhich enables search engines to rank the results they find in order of importance according to the terms entered in the search bar and the content proposed.

Improving your SEO with tdf*idf

With this in mind, it's clear that a good command of tdf*idf can have a beneficial impact on your web ranking. By targeting your keywords wisely, you can :

• • Increase the quality of your content by offering real added value to your readers, which will undoubtedly improve the time spent on your site, the number of visits and the rate of "hits". conversion;
  • Reducing the risk of over-optimisation avoiding placing certain words or expressions too often, which could be penalised by search engines (especially if the general context is not clear);
  • Stimulating the long tail by focusing on less common terms that are nonetheless specific to your sector and your products/services, in order to reach a more targeted and interested audience.

The tdf*idf is therefore an essential method for anyone wishing to optimise their web referencing and boost their online visibility.

By identifying the relevant keywords and adapting your content accordingly, you will be able to significantly improve the quality of your website and attract qualified traffic.