What Is TF IDF and How It Can Improve SEO?

June 28, 2020

What is TF IDF?

TF IDF comes from the English language. TF stands for term frequency. IDF stands for inverse document frequency – the inverse frequency of a word in documents. It is a method of calculating the weight of words based on the number of times they occur.

Let’s simplify:

TF IDF informs about the frequency of occurrence of the word and its importance in the context of all examined documents (e.g. websites).

This algorithm can be used as a method of content quality assessment by search engines.

Fact: TF IDF is used in anti-plagiarism systems.

Formula and sample calculations

Simplified formula

TF IDF = TF * IDF

where:

TF – is the number of occurrences of the word or phrase in the document (e.g. on a webpage), e.g. if the word “fox” appears 10 times in the article and the entire article has 500 words, TF is 10/500 = 0.02.

IDF – IDF is the logarithm of the number of documents in the corpus divided by the number of documents in the corpus that contain the studied keyword.

Having calculated separately TF and IDF, you can proceed to calculate the whole TF IDF, just multiply TF times IDF. In our example, it will be 0.02 * 0.52 = 0.01.

Fact: Popular words that often appear in articles are called “stopwords”. Example: If a word from the “stopwords” group, e.g. “to” appears in 10 documents in the corpus consisting of 10 documents, it is easy to calculate the IDF, i.e. log (10/10) = 0.

Why TF IDF helps SEO?

Currently, Google in its search results awards websites that have high-quality content, i.e. article describe a topic in-depth and in-detail.

A simple example:

If the article uses all closely related keywords and is of the right length, it is an important signal to the search engine that it covers the topic in a complete manner.

How to do TF IDF analysis for websites from top 10 search results?

To automate the calculation process and make the analysis as easy as possible, it is best to use the TF IDF tool. It is very easy to use. You only need to enter the addresses of the top 10 pages in Google for the query for which you plan to write an article. The tool will analyze all pages and will indicate sorted words and phrases according to the highest TF IDF weights.

But what if your article is already written and published and not optimized for TF IDF? In the TF IDF tool in addition to the 10 websites of your competitors, also enter your website address. This will give you information on exactly what words are missing on your webpage.

Summary

• TF IDF has a practical and very important usage in the SEO and it is especially helpful at optimizing and creating high-quality content.
• It’s a good idea to do a TF IDF analysis for competitors’ sites from Google’s top 10 organic search results before writing an article. Thanks to this, you will discover the words that should be included in the article.
• The TF IDF analysis should be performed especially for already published articles that do not appear in the top positions. Thanks to this, you can discover missing words that should be added to the content so that the article will be of higher quality and better describes the topic.
• Without TF IDF optimization, you run the risk of losing position in the future due to the possibility of your content being classified as low quality (content that not fully covers the topic).