Improvement Magnitude = Number of reassessments * Average improvement for those reassessments (for example : if there was 100 reassessments in a month, and those 100 reassessments had an average of improvement of 1.1 point, the improvement magnitude would be : 100 * 1.1 = 110)

Improvement Magnitude trendline : Difference between the improvement magnitude of a month and its previous year (for example : if the improvement magnitude was 500 in January 2017 and the improvement magnitude was 300 in January 2016, then the Improvement Magnitude trendline for January 2017 would be : 500 - 300 = 200)