# Quality of Distribution Index

The Quality of Distribution Index (QDI) represents an overall measure of student performance on statewide assessments in a given school year for a school or school district. The QDI is based on a relatively simple concept – if more students score in the higher proficiency levels on the test, the distribution of scores is more positive, if more students score in the lower proficiency levels, the distribution is more negative.

Schools get more points for students scoring at the higher levels than they do for students scoring at the lower levels. For example, for each percent of students scoring Advanced, a school or district gets 3 points; for each percent of students scoring Proficient, a school or district gets 2 points; and for each percent of students scoring Basic, a school or district gets 1 point. Schools get no points for students scoring at the Minimal level.

The formula for calculating QDI is:

QDI = (1 x % of students scoring Basic) + (2 x % of students scoring Proficient) + (3 x % of students scoring Advanced)

If 100% of a school’s students scored at the Advanced level, the school’s QDI would be 300, the maximum QDI possible. 