The passage comprehensibility of three diagnostic reading tests--the Stanford Diagnostic Reading Test, the Spache Diagnostic Reading Scales, and the Durrell Analysis of Reading Difficulty--was evaluated using the following text variables: content familiarity, vocabulary, the number of idea units in the text, the number of text-based inferences…

The Flesch readability index yields meaningful information about the responses of readers to texts. Because the formula is so simple, a group of English teachers wrote a program in BASIC that would count some obvious surface features of a text and calculate Flesch scores. Among the programing problems encountered were counting words (taking into…