Chiu, C. W. T., & Pearson, P. D. (1999, June). Synthesizing the effects of test accommodations for special education and limited English proficiency students [Paper presentation]. Council of Chief State School Officers (CCSSO) National Conference on Large-Scale Assessment, Snowbird, UT, United States. http://eric.ed.gov/?id=ED433362

Downloadable from ERIC database: https://files.eric.ed.gov/fulltext/ED433362.pdf

Many different accommodations were studied including: extended/unlimited time (extended-time), nonstandard accommodations (e.g., providing cultural-specific background information needed for full understanding), presentation format accommodations (e.g., computer and video), assistive devices, response format accommodations, and change in setting.

There were a variety of participants, different for each of the 30 studies used in the meta-analysis. Eight studies in the analysis were of elementary school students, nine of the studies were of middle school and high school students, 16 of the studies were in the postsecondary level, and four studies selected students from across a variety of age levels. The most common disability types studied were learning disabilities. The relevant studies appear to have been completed within the U.S. educational system.

Many different dependent variables were used, depending on the study.

Timing of the test was the most frequently investigated accommodation. Results of the meta-analysis indicated that extended time is beneficial to target populations when compared to standard time conditions (average effect size = 0.37). Regular education students also benefit from extended time, but with a lower effect size (0.07). The meta-analysis as a whole found that compared to conditions of no accommodation, students increased their scores by an average of 0.16 standard deviation. Relative to regular education students, special education students and limited English proficient students demonstrated an average accommodation advantage of 0.10 standard deviation. Altogether, the authors suggest that there is wide variability in observed effects among studies, and that improperly implemented accommodations could be disadvantageous to either the target population or the regular education population."