The Fog Test

Your guide to being understood

You need about 100 words from the writing you are "fogging". So select a passage that provides about that number in complete sentences. Count the words.

Count the sentences. Get the average sentence length by dividing the number of sentences into the number of words.

Count the technical words, trade terms, jargon and big words (i.e. those of three or more syllables). Ignore words that are only three syllables because of a suffix like "ing", "ed", or "ly" (eg. "injected").

Add the average sentence length and number of big words together.

Multiply that figure by 0.4 to get the Fog Index.

The Fog Index is the number of year's schooling your reader must have had in order to understand your message! For example, if your calculation comes in around 22, like so many articles do, it means that your reader needs about 22 years of education to understand it. That means 6 years primary plus 6 years secondary plus 3 degree courses at 4 years each… and there aren’t a lot of those readers around!

Looking at what newspapers do gives you a guide to where you should aim. Tabloid newspapers (such as Herald Sun or Evening News) fog at about 8, the more serious broadsheet press (Sydney Morning Herald or Auckland Herald) at about 10. They are written that way because that’s what the people who buy them can read and understand.

Ideally, you writing should fog at around 8 to 10 if you want it to be understood by your reader.

If what you have written scores higher you should try:

	Taking out the big words (3 syllables or more) and replacing them with simpler, smaller words.
	Making the sentences as short as possible.
	Replacing jargon with simple, non-technical words and phrases

Remember, when it comes to fog, less is better.