Comparison of four scoring methods for the reading span test.

This study compared four common methods for scoring a popular working memory span task, Daneman and Carpenter's (1980) reading span test. More continuous measures, such as the total number of words recalled or the proportion of words per set averaged across all sets, were more normally distributed, had higher reliability, and had higher correlations with criterion measures (reading comprehension and Verbal SAT) than did traditional span scores that quantified the highest set size completed or the number of words in correct sets. Furthermore, creation of arbitrary groups (e.g., high-span and low-span groups) led to poor reliability and greatly reduced predictive power. It is recommended that researchers score span tasks with continuous measures and avoid post hoc dichotomization of working memory span groups.