One common problem with report writing is that the sentences are often too long. If your sentences run over several lines, look at them more carefully to see if they can be made into 2 or more shorter sentences.

One way to help us decide if we are using appropriate language for our letter or report writing is to use a tool such as the “Fog Index” to help us.

The Fog Index is a simple mathematical tool for assessing the density of language, based on the proportion of long words and average sentence length.

Example

Leslie was a student at Sida Sandö in the early 1990s. He was on his way to Africa to work on a minor field study. With his permission we examined part of a report he had previously written concerning de-mining operations in Afghanistan.

The following extract from Leslie's report contains 77 words (numbers are not included in the calculation), consists of 5 sentences, and has 19 words of 3 or more syllables.

De-mining

Among the most crucial tasks to enable both reparation and rehabilitation is de-mining. Every year around 1000 civilian Afghans are mutilated by mines. Since 1990 Afghan NGOs have de-mined approximately 60 square kilometres of priority areas. It is estimated that around 350 square kilometres remains to be de-mined. At present level of funding and with the present capacity of the de-mining NGOs - around 20-25 square kilometres per year - the mine threat in the rural areas will be present for generations to come.

According to the Fog Index calculation we should first calculate the % of long words (19).

19 / 77 x 100 = 24%

We should then work out the average number of words per sentence.

77 / 5 = 15

We then add these two figures together to arrive at Leslie's Fog Index.

24 + 15 = 39

So, did Leslie’s report meet the guidelines set out by the Fog Index?

The ideal Fog Indexes are shown below:

Leslie’s Fog Index of 39 was acceptable for a report.

So the next time you write something, take a sample of about 200 words and calculate the Fog Index.

But remember, the Fog Index is only a guide - getting the right index doesn't guarantee anything by itself.