One of the Flesch indices of the readability of text, defined by the formula RE = 206.835 − (1.015 × average number of words per sentence) − (84.6 × average number of syllables per word). In practice, reading ease scores almost always lie between zero and 100. A reading ease score of zero indicates that the text is practically unreadable, 40 that it is difficult, 65 that it is standard, 85 that it is easy, and 95 that it is very easy. Reading ease scores have been found to correlate highly with ratings of readability and with measures of comprehension and retention. See also human interest score.