The measurement of reading comprehension: How not to trade construct validity for predictive power

This paper proposes a way to measure and understand individual differences in reading comprehension. The measure is based on the theory that individual differences in reading skill reflect differences in the processing capacity of working memory. The measure of processing capacity, called the reading span test, requires subjects to read aloud increasingly longer sets of sentences and to recall the final word of each sentence in the set. Reading span, the number of final words recalled, varies from two to five for university students. According to the proposed theory, poor readers devote so much capacity to processing the sentences, that they have less residual capacity for storing and producing the final words. The ability to keep information accessible in working memory is particularly crucial for the processes that integrate each ne word with previously read information. And, indeed, reading span is highly correlated with integration processes such as computing pronominal reference, monitoring and revising comprehension errors, and making inferences. The theoretical and predictive value of the reading span measure can be contrasted with the relatively limited value of existing atheoretical and theoretical measures of reading comprehension.