Here’s an article I wrote for ContentPeople, in April/May 2003, on Flesch readability.
Clarity is the commercial writer’s goal. With practice, it comes naturally. Finding the right level of readability is usually about gut feeling and consistency.
Increasingly, larger projects are looking to objective methods of measuring readability. The first – and most used – of these is the Flesch readability formula. Devised in the 1940s by American linguist Rudolf Flesch, it measures the average number of syllables per word and words per sentence. Using Flesch’s chart and a ruler, a score is given. An easier way to check a Flesch score is with a software tool, such as Microsoft Word’s grammar checking.
In his book How to write plain English, Flesch admits that using such “a mechanical gadget for this doesn’t seem like an intelligent approach”. His belief, though, is that it reflects the process the brain uses to read. Essentially, Flesch says that it’s easier to read shorter sentences that contain shorter words. Not exactly a major breakthrough.
Perhaps the major flaw of readability formulae is their disregard for context. As John Wild, of the Plain English Campaign notes, “‘The cat sat on the mat’ has exactly the same readability index as ‘The mat sat cat the on’.” It has to be assumed, then, that anyone whose writing is measured using Flesch, or other formulae, already has a mastery of English.
Echoing John Wild’s reservations, Phil Scholfield, of the University of Essex, sees readability formulae as of limited usefulness. “While it is true that usually longer sentences and longer words are harder, that is not always so and several other things can make a text difficult, such as the complexity of its organisation and the difficulty of its thought/content.”
In an effort to achieve a higher Flesch readability score, it can be tempting to forget the actual, human readability of a piece and start slashing away at words. Almost slipping into the spirit of George Orwell’s Newspeak, Flesch suggests that writers should “take first aim at words with prefixes and suffixes, like establishment, available or required” and replace them with “a two-word combination like setting up, in stock or called for“. Rather doubleplusungood for subtlety in English, I’d say.
To be fair to Flesch, he admits that his formula is only useful as a guide. Certainly, for projects with large numbers of writers, the Flesch system can help to produce a uniformity of style. However, as web based translation services prove, language cannot be reduced to computerised rules.