Idaho Percentile Results for the 2015 and 2016 ISAT (SBAC) English Language Arts and Mathematics Tests in Grades 3-8 and 10

Idaho uses the English Language Arts and Mathematics tests from the Smarter Balanced Assessment Consortium (SBAC) for the Idaho Standard Achievement Tests (ISAT). ISAT results have been have been reported almost exclusively as "percent proficient" statistics (i.e., the percentage of Idaho students who performed at the "A" level on the ISAT). This paper examined whether one traditional normative statistic derived from ISAT scale scores--percentiles--can provide reasonable informative descriptions of student achievement. The 10th, 25th, 50th, 75th and 90th percentiles were identified from the ISAT 2015 and 2016 tests of English Language Arts and Mathematics. These percentiles provided the opportunity to look at student performance across the board (high, high average, average for grade level, low average, and low) and how it changes over time. The changes from 2015 to 2016 were tallied and presented in tabular format. The changes were also presented graphically via boxplots and line graphs. The tables and figures indicated that several grades in both subjects exhibited percentile gains across the board while only one grade had losses across the board in English Language Arts. This information was not discernible in percent proficient statistics, but important nonetheless for a comprehensive accountability system. Few Idaho districts and charter districts have staff with the skills and time to perform percentile analyses for the students in their districts and schools. With resolve, however, each year the state could provide the five percentiles with templates for tables and graphs to each group for which it reports ISAT "percent proficient" results. The following are appended: (1) ISAT English Language Arts 2015 and 2016; and (2) ISAT Mathematics 2015 and 2016 tables.