Automated Readability Checker
Readability - a 'free' automated checker
For a number of years there have been formulae for checking the 'readability' of written work and now they are computerised. The theory is based on ensuring that short words are used rather than long words and short sentences rather than long (average number of syllables per word and average number of words per sentence).
There is a simple way to check the readability of your own work. If you use Microsft Word (who doesn't?) then there is a little known gem hidden away called the Flesch Reading Ease measure. Just click on Tools, Spelling & Grammar. Go right through the spell check and there it is. Ignore the Flesch-Kincaid Grade Level (it's not helpful). The Reading Ease measure will give a rating - the higher the score the better. As an example, I ran two important documents through it (opposite)....
NB Do remember that the final test of whether any piece of writing meets its goal of communicating happens when humans read it!
Example 1. Declaration of Independence
"We hold these truths to be self-evident, that all men are created equal, that they are endowed by their Creator with certain unalienable Rights, that among these are Life, Liberty and the pursuit of Happiness." (Score 43.2%)
Example 2. EU Charter of Fundamental Rights
"This charter reaffirms, with due legal regard for the powers and tasks of the Union and the principle of subsidiarity, the rights as they result in particular, from the constitutional traditions and international obligations common to the member states, the European Convention for the protection of human Rights and fundamental freedoms, the Social Charter adopted by the Union and by the Council of Europe and the case law of the Court of Justice of the European Union and of the European Court of Human Rights." (a single sentence - score 0%)