What is a WDF*IDF analysis?
A WDF*IDF analysis is an advanced method of text analysis used in search engine optimization (SEO). WDF*IDF stands for Within Document Frequency times Inverse Document Frequency. The goal of the analysis is to make a text more relevant for particular search terms by working out how much weight each keyword should carry.
The method shows which words a text uses more or less often than an average document from a given collection, a website or a news feed for example. The formula helps you find the optimal frequency for your keywords so that search engines rate the page higher, without walking into the trap of keyword stuffing.
How does a WDF*IDF analysis help my SEO?
A WDF*IDF analysis is a powerful tool in SEO because it helps you shape content that search engines read as particularly relevant for a given keyword.
By adjusting keyword weighting on the basis of the analysis, site owners can make sure their content stays natural and informative for search engines and for readers alike. That often leads to better placements in the search results, a higher click rate and, in the end, more traffic.
The method also helps you find and close content gaps, meaning topics your own content does not yet cover well enough although they matter to your target audience. If you would rather have that work done for you, it is part of our SEO services.
How do I run a WDF*IDF analysis?
To run a WDF*IDF analysis you first need a set of documents to serve as your reference, usually the top results a search engine returns for the keyword in question. You then look at how often each word appears in the document you want to improve (WDF) and how often those words appear on average across the reference set (IDF).
Dedicated SEO tools such as Ryte or Sistrix can automate that work and give you a simple interface for reading the data. The result is a list of words that should either be emphasized more or used less, so that the text gains in relevance and stays readable.
Which tools are there for WDF*IDF analysis?
Free tools for WDF*IDF analysis
- WDFIDF-Tool: a version limited to three free queries per day.
- Keyword Tool Dominator: has a limited free version for simple keyword frequency counts.
- SEOlyze (30 days free): offers a basic WDF*IDF analysis as part of its services.
- SEO PowerSuite: offers a free version with a reduced feature set.
Paid tools for WDF*IDF analysis
- Ryte: offers an extensive WDF*IDF toolbox that gives you a deep look at content optimization. Ryte is known for its detailed reports and its professional SEO features.
- Sistrix: a widely used SEO tool that offers detailed WDF*IDF analysis and stands out for its reporting.
- SEMrush: alongside its other SEO tools it also has a WDF*IDF feature. SEMrush is known for a broad range of tools and reports that suit large SEO campaigns.
- Surfer SEO: uses WDF*IDF analysis to improve web content and offers friendly features aimed at content marketing and SEO.
- Xovi: another all-in-one SEO tool with a WDF*IDF feature. It is particularly useful for detailed keyword work and for tuning online marketing strategies.
More terms around content and rankings are collected in our SEO glossary.
