Validity evidence based on test content is important for educational tests to demonstrate the degree to which they fulfill their purposes. Most content validity studies involve subject matter experts (SMEs) who rate items that comprise a test form. In computerized-adaptive testing, examinees take different sets of items and test "forms" do not…

The articles in this special issue of the "Journal of Applied Testing Technology" represent significant steps forward in the area of evaluating the validity of methods for assessing the educational achievement of students with disabilities. The studies address some of the most difficult student groups to assess--students with learning…