Sample Frequency in Application of Dale-Chall Readability Formula
Marie Burkhead, Greg Ulferts · Journal of Reading Behavior · 1977
Using 48 college texts, comparisons were made of Dale-Chall Readability Formula results based on samples taken from various page intervals. Results indicate that for the 48 textbooks examined, samples taken at 20, 30, 40, and 50-page intervals are as reliable as samples taken from 10 page intervals.