Chapter 2. Considerations in developing vertical scales for language tests

Abstract

This chapter provides a framework for building vertical scales, for language assessments in general and for the TOEFL® Family of Assessments in particular. Topics covered include aspects of vertical scale design (growth definitions, vertical articulation, data collection), statistical methods for vertical linking, and evaluation and maintenance of the resulting vertical scale. Also discussed are challenges associated with vertical scaling, as noted in the research literature, in general and as pertains to language proficiency assessments.