Brown, P. J. (1999). Findings of the 1999 plain language field test: Inclusive comprehensive assessment system . University of Delaware Education Research and Development Center. https://udspace.udel.edu/handle/19716/2336

(Publication T99-013.1) Attachment study from the Inclusive Comprehensive Assessment Systems Project

Two versions of an assessment were administered. One version contained items in their original format, and the other version incorporated the features of "Plain Language" translation, substituting common words and simplifying phrasing.

A total of 462 students in grades 5 and 8 from 30 schools across six school districts throughout Delaware (U.S.) participated. Special education students and Limited English Proficient (LEP) students were included in the sample. About 36% of the sample was students with disabilities, but participants' specific disabilities were not reported.

Two versions of the mathematics and science assessments were administered, resulting in a compilation of 992 separate assessment scores from the participants. Each version consisted of a variety of grade-appropriate multiple choice, short answer, and open-ended items. The items on all versions were identical in every other aspect.

No significant differences were found between the performance of students who completed the original version versus the performance of students who completed the Plain Language version for any subgroup of students (LEP, students with disabilities, and students without disabilities) in mathematics or science at either grade 5 or grade 8.