What Is WDF*IDF?
Imagine that you’re standing in a room where everyone is repeating the same set of words, over and over again, all at the same time. You don’t hear anything because, well, you can’t — it all just becomes a low hum. But then you do hear someone. Someone speaking their unique thoughts, in coherent sentences, and with a clear voice. Instead of just saying the words over and over again, that person is saying something about the words. Speaking to you so that you can hear them. Welcome to the internet, and the power of WDF*IDF.
What does WDF*IDF mean?
The meaning of WDF*IDF lies in a surprisingly simple acronym — with WDF meaning “Within Document Frequency” and IDF meaning “Inverse Document Frequency” — it’s about comparing how often a word is used on a page of your website with how often that word shows up on other sites.
What about the asterisk? It indicates that these two values are multiplied together. The WDF*IDF formula actually uses logarithms (see below) but we’re not going to get that mathy in this article.
The beauty of using a tool that analyzes WDF*IDF is that it will look at more than just the frequency and density of keywords. It will check to see how those words interact with each other.
Let’s take a closer look.
How does the WDF*IDF formula work?
WDF*IDF analysis produces a list of terms that can signal to search engines that your site is more relevant to readers than another site if you then include them in your content. This formula is all about seeing if your site is on par with other sites, with more relevant content moving you towards the top of the search results.
Looking at keywords in this way adds a layer of strategy on top of your already engaging content. It’s certainly a given that everyone wants to have captivating text. First impressions matter to keep readers on your pages — you want them to stay past that 10-second mark!
But before readers even have the chance to read your content, they have to find it. Most often they’ll go through a search engine using a unique search query. Using specific keywords on your page, and using them well, will help you leverage one of many on-page ranking factors.
Remember our opening scenario, where everyone was saying the same thing over and over again? Could you feel the mind-numbing redundancy? Hold onto that feeling as you think about how you create your content. Again, it’s not just what you say, but how you say it. The WDF*IDF formula provides valuable insight into how your content stacks up against your competitors, specifically because it accounts for your keywords, their frequency, and their usage.
What should I watch out for when doing a WDF*IDF analysis?
There are two potential weak spots to be aware of when utilizing a WDF*IDF tool. One is in the formula, and one is how you apply the results.
With the formula itself, you need to have enough other texts to compare yours to. If your sample set is too small, or the comparable pieces are too short, it will impact the analysis. After all, there’s a reason that it’s not simply W. D. F! The within document frequency of your content has to be compared against that of other sites, which is exactly what search engines are doing. Additionally, WDF*IDF tools don’t distinguish between different types of content, so they will analyze everything on the page – captions, bylines, item descriptions, etc. — not a complete deal-breaker, but definitely something to pay attention to.
How You Apply the Results from a WDF*IDF Tool is Vital
Yes, the analysis will produce a list of key terms that you should consider adding to your text. But this isn’t to say that you should just pour the keywords onto the page! You still need well-written content that keeps in mind structure, flow, semantics, and syntax. And no keyword stuffing! Partly because it’s not nearly as tasty as Thanksgiving stuffing, but mostly because it could ruin your search rankings.
Is WDF*IDF for me?
It is! Don’t get me wrong – I know there’s a lot to consider when it comes to Google ranking factors. So. Many. Things. But with the positives dramatically outweighing the negatives, so you should spend some time learning about WDF*IDF. Carefully researched keywords, that have been compiled based on broad comparison and implemented using a keen eye can dramatically improve your search rankings.
Where can I find a WDF*IDF tool?
Between paid software, free sites, and trial subscriptions, there are several options out there. (A quick note – some European sites use the acronym TF instead of WDF, meaning “Term Frequency.” It’s interchangeable with “Within Document Frequency,” so when you see TF*IDF, you’ll already know what that means!)
Free tools can help get you started, but they do have limitations. Some free tools limit how often you can search or how broad a set of content they’ll pull for comparison. Take a look at one of these two tools:
Registering for a trial version of a paid site before signing up for a longer commitment gives you a chance to see if the specific software (along with its interface and the company’s customer service team) is a good fit for you. Paid options have expanded features and are more robust. These three sites offer trial versions of varying lengths.
If you’re ready to jump right into a paid plan, these sites are also options:
Video Tutorial – WDF*IDF Analysis using Text Tools
Here’s a quick walk-through showing how I use Text Tools to run a WDF*IDF analysis:
Using WDF*IDF analysis on your content is one way to improve your search rankings, but it’s just one of many techniques that will improve your online visibility.