Considerations for Equating Alternate Assessments: Two Case Studies of Alternate Assessments Based on Alternate Achievement Standards

The development of alternate assessments for students with disabilities plays a pivotal role in state and national accountability systems. An important assumption in the use of alternate assessments in these accountability systems is that scores are comparable on different test forms across diverse groups of students over time. The use of test equating is a common way that states attempt to establish score comparability on different test forms. However, equating presents many unique, practical, and technical challenges for alternate assessments. This article provides case studies of equating for two alternate assessments in Michigan and an approach to determine whether or not equating would be preferred to not equating on these assessments. This approach is based on examining equated score and performance-level differences and investigating population invariance across subgroups of students with disabilities. Results suggest that using an equating method with these data appeared to have a minimal impact on proficiency classifications. The population invariance assumption was suspect for some subgroups and equating methods with some large potential differences observed.