ISAT Effect Size Results for Idaho English Language Arts & Mathematics Grades 3-8 and 10 2015-2018 Bert Stoneberg, Ph.D. K-12 Research Idaho http://k12researchidaho.com
“Practical significance” of the difference between two mean scores for an ISAT subject/grade test Legend for this sample “Effect Size” graph for 2015-2017 Magnitude of the 2015-2016 gain, i.e., practical significance of the difference between the average/mean scores Magnitude of the 2016-2017 loss , i.e., practical significance of the difference between the average/mean scores Magnitude of the trend gain/loss from 2015 to 2017. The trend line is updated after each assessment (i.e., 2016 + 2017 magnitudes).
Calculation of “Effect Size” The effect size or the practical significance of the difference between two means or the magnitude of the difference between two means is calculated by dividing the difference between two means by their pooled standard deviations.