If you think that computing breeds geeks, try ‘ham’ radio.

As a licensed ham (callsign M1BWR), I confess to sitting on beaches blurting “CQ DX” into the mike. But being a ham teaches you the key elements of communication more vividly than abstract models such as Shannon’s: you quickly appreciate how successful communication requires two ends and a middle.

If you need to communicate much at all – whether inviting someone to attend a medical screening clinic, or informing them how to configure their Mac – your medium is almost certain to be written words. Unfortunately, despite centuries of education acts and pedagogic effort, a large proportion of the adult population of the UK and USA remain functionally illiterate.

Depending on how you measure that nebulous property, the proportion ranges between 10% and 45%. When you’re selling beautifully designed computers, you may not have to worry about ‘the rest of us’ who cannot read much. When you set your sights on a real mass market, with iPhones for instance, then getting instructions across intelligibly becomes critical.

One approach is to simplify your English writing, to use ‘plain words’, Sir Ernest Gowers’ revolutionary concept for rendering accessible the missives of the Civil Service. Several different readability metrics are now available, although it is equally plain that none is particularly trustworthy.

Among the most popular is the Flesch-Kincaid grade scale, which gives the number of years of full-time education necessary to understand the text. It is computed from the average sentence length and the average number of syllables per word. Inevitably it is not hard to construct meaningful texts that contain many hard but short words, in relatively short sentences, and to end up with a misleading grade. However, over samples of reasonable length and variation, it is not a bad metric to use. The average news story in popular tabloid newspapers like The Sun runs to a Flesch-Kincaid grade of about 9, meaning that you would expect someone of about 14 years of age and average reading ability to be able to understand it fully.

Dear reader, you will be delighted to know that you are made of sterner and more literate stuff. For articles on this blog have a typical Flesch-Kincaid grade of about 12, requiring average reading skills at the age of 17 years or so. If English is not your first language, then you should be truly proud of your English reading skills.

But if you use Microsoft Word’s built-in tool for measuring Flesch-Kincaid grades, you could be seriously misled. In case you have not found this ostensibly useful feature, you first need to enable it in the Spelling and Grammar pane of Word’s Preferences (it’s at the bottom of the Grammar section, as Show readability statistics), then check the spelling with the Spelling and Grammar command in the Tools menu.

Try it on a range of documents, and you may be puzzled to discover that, whilst the more cryptic Flesch Reading Ease score can sink towards ‘completely opaque’ at 0 (but never below), the Flesch-Kincaid grade never rises above 12.0: even when fed a notorious sentence from Proust, thanks to Wikipedia. This is still true today of Word 2011 and the latest pre-release of Word 2015.

This bug is perhaps one of Word’s most bizarre. The Flesch-Kincaid grading formula is hardly rocket science, and Word’s failing in this respect has been pointed out by many different users over a long period in different versions. But for reasons known only to Microsoft, Word will never tell you that your document is too tough for a 17 year-old. As ever, some who dislike being so patronised have created their own solution in Flesh (free), a neat little Java application that will tell you the Flesch-Kincaid reading grade of your documents honestly.

Sadly for many of the adult population, any form of words will be too much to bear. Perhaps Plasq’sComic Life will allow you to pass your message better with pictures.

It will not help me in my ham radio, of course. But given the right transmitter and receiver, I have been able to chat with hams in Australia, over 10,000 miles from the beach at Bembridge, Isle of Wight, using just 5 watts and a few bits of aluminium pole. Is that not ultimately geekish?

Updated from the original, which was first published in MacUser volume 22 issue 7, 2006.