even facilitate the measurement goals of the assessment. Accommodations are generally intended to offset a distortion in scores caused by a disability, so that scores from the accommodated assessment would measure the same attributes as the assessment without accommodations administered to individuals without disabilities. But, like any alteration in standardized administration procedures, accommodations may alter what an assessment measures, even when it appears on its face not to do so.

We use modification to refer to alterations of the content of an assessment.¹¹ Most content modifications are likely to change what a test measures. For example, educators may delete from an assessment specific items, subtests, or tasks that are deemed inappropriate or impractical for a specific examinee, or they may replace such a task with an alternative that would be more reasonable for that individual.

One common type of modification of tests is the administration of easier forms intended for younger children ("out-of-level testing"). Under certain restrictive conditions, out-of-level testing may preserve the measurement functions of an assessment, but it is unlikely to do so in the case of many standards-based assessments.¹² Moreover, testing that is substantially out of level may not produce comparable results (Plake, 1976), and out-of-level testing may be problematic in subjects in which curriculum content differs markedly across grades. Moreover, standards-based assessments are typically not constructed, administered, or reported in ways that would help preserve their measurement functions if administered out of grade. Perhaps most important, they are typically reported in terms of standards that are set within grades and are not linked between grades. Accordingly, in the case of the assessments used in standards-based reform, it is safest to consider out-of-level testing to be a modification that threatens performance comparability, not an accommodation that has the potential to maintain or even enhance it.

Finally, in some instances, students with disabilities may be administered different assessments rather than accommodated or modified versions of the same assessments administered to other students. These different tests may or may not be related conceptually to the regular assessments, but they are constructed as distinct assessments. Examples include Kentucky's alternative portfolio assessments and Maryland's Independence Mastery Assessment Program (IMAP) assessment, both of which are administered to a small percentage of students with