Readability Score

The definition of a readability test is any form of assessment of the readability (easy to read) of a text, a book, a novel, a message, a story, a article.

In practice, this is usually a score that is used to associate a writing with the minimum recommended age for reading it.

To calculate the score, 4 values are often used to characterize the text:

$ C $ the number of characters

$ S $ the number of syllables

$ W $ the number of words

$ W_3 $ the number of words with 3 or more syllables (polysyllabic word)

$ X $ the number of sentences

The formula for calculating the Flesch readability score is $ FRES = 206.835-1.015\frac{W}{X}-84.6\frac{S}{W} $

The calculated value is usually between 0 and 100.

Formula similar to the Flesch score, it has been reworked to correspond to Anglo-Saxon school levels (depending on the number of years of study): $ FKGL = 0.39\frac{W}{X}+11.8\frac{S}{W}-15.59 $

The Automated Readability Index is calculated $ ARI = 4.71 \frac{C}{W} + 0.5\frac{W}{X}-21.43 $

The returned value corresponds to the level of studies necessary to read the text (see above FKGL)

The SMOG level (for Simple Measure of Gobbledygook) is calculated $ SMOG = 1.043 \sqrt{ \frac{ 30 \times S_3 } {X} } + 3.1291 $

The returned value corresponds to the level of studies necessary to read the text (see above FKGL)

The Coleman – Liau index is calculated $ CLI = 5.88 \frac{C}{W} - 2.96\frac{X}{W} - 15.8 $

The returned value corresponds to the level of studies necessary to read the text (see above FKGL)

The Gunning Fog index is calculated $ GFI = 0.4 \left( \frac{W}{X} + 100 \frac{S_3}{W} \right) $

The returned value corresponds to the level of studies necessary to read the text (see above FKGL)