Making Sense of the Metrics: Student Growth, Value-Added Models, and Teacher Effectiveness. Bulletin. Issue 19

The nation is showing an unprecedented focus on increasing the rigor in education and preparing students for college. The college readiness trend is driving changes in the ways in which the nation uses student test data. Educational data are no longer limited to static data snapshots showing the status of a student performance at one point in time. Instead data are linked grade-to-grade and course-to-course, to create a longitudinal measure of student performance. Inferences about student progress are now made using status as well as growth models. The new national trend is to enhance the ability to draw inferences about student growth by collecting more direct evidence from longitudinal student data. The use of longitudinal data expands beyond informing about student progress to evaluating teachers and educational leaders. President Obama has repeatedly highlighted the need for teacher effectiveness measures and offered incentives for those who are willing to implement them. The Department of Education awarded billions of dollars from the Race to the Top fund to 11 states and the District of Columbia in 2010. In granting the awards, the Department evaluated state applications for which 28% of the points were dedicated to a section entitled "Great Teachers and Leaders." As part of the application requirements, states had to develop and describe a system for assessing teacher effectiveness that included student achievement data and provided annual effectiveness ratings for all teachers. States awarded the Race to the Top funds are currently working to implement their plans for teacher effectiveness systems, with most relying on student growth measures as essential measures in their systems. The use of student score changes in different applications has led to confusion in the use of terms and concepts. Terms such as student growth, value-added models, and teacher effectiveness are often used interchangeably. The differences in these three measures are significant. Using one when another is intended has impeded the nation's ability to develop these measures well and to use the information in optimal ways. The goal of this paper is to define student growth, value-added models, and teacher effectiveness, the three terms that are often confused. Furthermore, the paper compares and contrasts features of these three measures and identifies next steps needed for advancing the use of these measures for educational reform.