This study used a non-experimental, one-group, pretest-posttest design to compare the scale scores on the 2017-2018 and 2018-2019 Mathematics sections of the New Jersey Student Learning Assessment (NJSLA). This investigation compared the 2018 New Jersey Student Learning Assessment in Mathematics (NJSLA-M) scale score means for sampled special education students in Grades 4-8 to the 2019 NJSLA-M scale score means for the same group. A Paired-samples t-Test was used to determine what statistical differences exist, if any, between the scores 2017-2018 results of the students prior to receiving instruction based on learning progressions and the 2018-2019 results after receiving instruction in learning progressions. Results show that there was no significant difference in the pretest and posttest mean scale scores suggesting that there was no significant impact of the learning progressions model of student performance after one year of exposure. [The dissertation citations contained here are published with the permission of ProQuest LLC. Further reproduction is prohibited without permission. Copies of dissertations may be obtained by Telephone (800) 1-800-521-0600. Web page: http://www.proquest.com/en-US/products/dissertations/individuals.shtml.]