Introducing Second Language Assessment

In Chapter 8, the author introduces readers to item-level statistics and Cronbach’s Alpha as an estimate of internal reliability, all of which are useful for analyzing and revising dichotomously scored language assessments. The chapter focuses on two item-level statistics: item facility, or how easy an item is for a group of test takers, and point-biserial, which provides an indication of how well an item measures the targeted language ability. The author shows readers how to calculate these values and interpret their meaning for particular language assessment contexts. The chapter concludes with a discussion of how to calculate and interpret reliability based on Cronbach’s Alpha. The author also provides guidelines for interpreting reliability estimates for various language assessment contexts. An appendix provides guidance for using Excel software to calculate these statistics.