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By Russ Allen, Ph.D, Chris Gallant, J.D., Craig Leedham, Ph.D, and Jeff Leverich, Ph.D
Table of Contents Concerns and observations about Value-added Assessments |
Introduction
It is commonplace in this country to compare students’ test scores
over time. This is routinely done by educators and the media. These
types of comparisons often provide useful information to parents, policy
makers, and the general public, and as a result, make schools more accountable
to the community. In most instances, however, time-based comparisons
tend to examine different cohorts of students and also tend to be cursory.
That is, differences in test scores are reported with little or no explanation
for those differences.
Proponents of measuring growth in test scores maintain that we need to do a better job, and many suggest that value-added assessment (also called value-added measurement) is the next logical step because it not only measures the magnitude of growth, but also allows us to identify which teachers contribute most to improving student learning.
This paper summarizes what is known about value-added assessment by addressing some of its basic concepts and underlying assumptions, as well as the disagreements that exist among measurement experts. As the reader shall discover, the word that best describes value-added assessment is “controversial.”
Valued-added Assessment: Defined
Value-added assessment is a method of analyzing and reporting student
test results based on improvement (“growth”) in standardized
test scores over two or more points in time. This procedure contrasts
with more traditional approaches, which analyze and report test results
at a single moment in time. Both methods use standardized achievement
tests, but value-added measurement compares each student’s latest
test score with the same student’s past test score to determine
growth or improvement.
Value-added assessment assumes that teachers are the most important factor affecting student learning, and that the amount of “value” that the teacher “adds” to each student can be precisely measured. However, many experts in educational measurement express serious concerns about the methodology and about the assumption that teachers are the single most important factor in affecting student learning. The history of educational research has demonstrated again and again that factors such as poverty and parents’ level of education make a difference.
Among the benefits claimed by proponents of value-added assessments are the following:
