Lexile Framework At the height of the controversy about the readability formulas, the founders of MetaMetrics, Inc. (Stenner, Horabin, et al. 1988a) published a new system for measuring readability, Lexile Framework, which uses average sentence length and average word frequency found in the American Heritage Intermediate Corpus (Carroll et al. 1971) to predict a score on a 0- 2000 scale. The AHI corpus includes five million words from 1,045 published titles to which students in grades three through nine are commonly exposed.

The cognitive theorists had claimed that different kinds of reading tests actually measure different kinds of comprehension. The studies of the Lexile theorists (Stenner et al. 1988b, Stenner and Burdick 1997) indicate that comprehension is a one-dimensional ability that subsumes different types of comprehension (e.g., literal or inferential) and other reader factors (e.g., prior knowledge and special subject knowledge). You either understand a passage or you don't.

The New Dale-Chall Readability Formula In Readability Revisited: The New Dale-Call Readability Formula, Chall and Dale (1995) updated their list of 3,000 easy words and improved their original formula, then 47 years old. The new formula was validated against a variety of criteria, including:

• 32 passages tested by Bormuth (1971) on 4^th to 12^th-grade students.
• 36 passages tested by Miller and Coleman (1967) on 479 college students.
• 80 passages tested by MacGinitie and Tretiak (1971) on college and graduate students.
• 12 technical passages tested by Caylor et al. (1973) on 395 Air Force trainees.

The new formula was also cross-validated with:

• The Gates-MacGinitie Reading Test
• The Diagnostic Assessments of Reading and Trial Teaching Strategies (DARTTS)
• The National Assessment of Reading Progress
• The Spache Formula
• The Fry Graph
• Average judgments of teachers on the reading level of 50 passages of literature

Fig 12. Jeanne S. Chall created the Harvard Reading Lab and directed it for 20 years.

The new formula correlates .92 with the Bormuth Mean Cloze Scores, making it the most valid of the popular formulas.

At the time of writing this, the new Dale-Chall formula is not yet available on the Internet. It was once available in a computer program, "Readability Master," but is hard to find. You can easily apply the formula manually, however, using the instructions, worksheet, word list, and tables provided in the book. The book also has several chapters reviewing readability research, the uses of the formulas, the importance of vocabulary, the readability controversies, and a chapter on writing readable texts.