The New Dale-Chall Formula improves the original Dale-Chall Readability Formula as expounded in
A Formula for Predicting Readability in 1948. The creators of this formula were
Edgar Dale and
Jeanne Chall.
Edgar Dale was a professor of education at Ohio State University and a well-known authority on communications. He devoted much of his life to improve the readability of reading materials, such as books, pamphlets, and newsletters. Jeanne Chall was the founder-director of the
Harvard Reading Laboratory for 20 years. She was also the reading consultant for the hit TV show
Sesame Street and The Electric Company. She was in the forefront in the battle for teaching early reading systematically
with phonics. Many professionals consider her book,
Learning to Read: The Great Debate, a great contribution in the phonics debate.
Rudolph Flesch and his
Flesch Reading Ease Formula inspired Edgar Dale and Jeanne Chall to revolutionize the way most people perceive documents. Dale and Chall created
The Dale-Chall Formula for adults and children above 4th grade as a way to improve upon the Flesch Reading Ease Formula.
The Dale-Chall Formula was unique because, unlike other formulas that use word-length to assess word difficulty, the Dale-Chall Formula uses a count of ‘hard’ words. The Dale-Chall Formula calculates the US grade level of a text sample based on sentence length and the number of ‘hard’ words. These ‘hard’
words are words that do not appear on a specially designed list of common words familiar to most 4th-grade students.
The original Dale-Chall Formula had a list of 763 non-hard or familiar words. However, the New Dale-Chall Formula, revised by
Readability Revisited: The New Dale-Chall Readability Formula, in 1995 expands the list of
familiar words to 3000.
