Spache readability formula
The Spache readability formula is a readability test for writing in English, designed by George Spache. It works best on texts that are for children up to fourth grade. For older children, the Dale–Chall [readability formula] is more appropriate.
It was introduced in 1953 in Spache's "A new readability formula for primary-grade reading materials,", and has subsequently been revised.
Calculation
The method compares words in a text to a set list of everyday words. The number of words per sentence and the percentage of unfamiliar words determine the reading age.The original formula was:
The revised formula is: