Modified Achievement Tests for Students with Disabilities: Basic Psychometrics and Group Analyses Ryan J. Kettler Vanderbilt University CCSSO’s National Conference on Student Assessment June 2008

Reliability and Concurrent Validity with a Proficiency Tests CAAVES Item Mod Data 20082

Concurrent Validity with Participation Criteria CAAVES Item Mod Data 20083

4 Reading: Descriptive Statistics for Unmodified and Modified Tests

Distributions by Group and Condition in Reading CAAVES Item Mod Data Students without Disabilities, Ineligible Students with Disabilities, Ineligible Students with Disabilities, Eligible

Effect Sizes of Modifications on Reading Performance CAAVES Item Mod Data 20086

Group Improvement by Condition in Reading CAAVES Item Mod Data 20087

Mean Item Difficulty by Group and Condition in Reading CAAVES Item Mod Data * Student abilities were equated using a Rasch model.

CAAVES Item Mod Data Math: Descriptive Statistics for Unmodified and Modified Tests

Distributions by Group and Condition in Math CAAVES Item Mod Data Students without Disabilities, Ineligible Students with Disabilities, Ineligible Students with Disabilities, Eligible

Effect Sizes of Modifications on Math Performance CAAVES Item Mod Data

Group Improvement by Condition in Math CAAVES Item Mod Data

Mean Item Difficulty by Group and Condition in Math CAAVES Item Mod Data * Student abilities were equated using a Rasch model.

Upcoming Analyses: Difficulty Change on Individual Items CAAVES Item Mod Data Students without Disabilities, Ineligible Students with Disabilities, Eligible

Conclusions Assessments can be made more accessible for eligible students (with disabilities who have persistent academic difficulties). Modifications can change the difficulty of tests and items without invalidating the resulting scores. Much more work needs to be done! CAAVES Item Mod Data