What is the Power Law? Does NHA use averages when calculating student scores?
Both the power law and average are methods of estimating a student’s level of learning based on past performance. Which method gives the most accurate estimate depends on the available scores. When scores show a growth trend over time, the power law gives the most accurate estimate. For example, if scores for a particular measurement topic are ‘2, 2.5, 3, 4’, a growth trend is evident. The student score would be calculated using the power law, which in this case would be a 4. When scores do not show a growth trend over time, the average gives the most accurate estimate. For example, if scores for a particular measurement topic are ‘3, 2, 3, 2’, no growth trend is evident. The student score would be calculated using the average, which in this case would be a 2.5. GradeBook automatically analyzes all of the scores in a measurement topic and then uses the method—average or power law—that most accurately estimates student proficiency. Here is a simple way of thinking about it: when measuri
