The Fog Index

I was speaking to my mum the other day and she told me to research the fog index, and that I would probably be surprised by what I discovered. My first thought was that is was something to do with the weather, which judging from the name would be a natural assumption. Perhaps they had some sort of rating system as to how dense the fog is, as to how long it will take to clear. However it turns out that I was way off! The fog index's full name is, the Gunning fog index and it measures the readability of English writing. Robert Gunning is an American businessman who created the fog index in 1952, and the name apparently derives from how foggy a piece of writing is to understand. The lower the score on the index, the clearer, or less foggy, a piece of text is to understand. The index is most commonly used to determine if a text is pitched at the right level for the intended audience and as a rule of thumb, text which is intended to be understood universally, requires a fog index of eight or lower.

There is a formula which is used to determine the fog index of a piece of text, which incorporates the number of words in a sentence, and the number of complex words in a sentence, divided by the overall number of words. The full formula and how to determine the fog index of a text can be found on Wikipedia, however a much more expedient way of measuring the fog index is to take a block of text, approximately 100 words (one or more full paragraphs), copy, then paste the sentence into the Gunning fog Index website, and click calculate. The Gunning fog index rates this entire blog at a 14.79 on the index, which means that it won't be understood universally. So if you are reading and understanding this blog, then feel special, because, according to the Gunning fog index, this text is a little too foggy to be understood by every English speaker in the world.