The Flesch Score (aka the Flesch Reading Easiness) indicates how hard it is to read a piece of contemporary academic English. Hard stuff has low scores (low readability) and easy stuff has high scores (high readability).
The score of a text is calculated using a formula involving the number of words, the number of syllables in those words and the number of sentences. The scores range from 0-100 and look like this:
90.0–100.0 easily understandable by an average 11-year-old student
60.0–70.0 easily understandable by 13 to 15-year-old students
0.0–30.0 best understood by university graduates
A typical mass market magazine has a readability index of about 65. Time magazine scores about 52, and the Harvard Law Review has a score in the low 30s.
What’s your score? If you’re using Microsoft Word you can use the Tools menu to find it out.