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Assessing a Teacher's Value

New York Times
September 6th, 2010

This piece, from the New York Times, features the voices of eight authors on the merit of evaluating teachers based on value-added tests. The authors include Linda Darling-Hammond; math teacher Vern Williams; Kevin Carey, from the Education Sector; Lance T. Izumi, Pacific Research Institute; Education Trust's Amy Wilkins; author Diane Ravitch; Marcus Winters of the Manhattan Institute; and Jesse Rothstein, from U.C. Berkeley. Darling-Hammond's piece is below. Others can be found at the New York Times web site

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Introduction

Reed Saxon/Associated Press

The Wonderland Avenue school in Los Angeles. It is one of hundreds of schools included in a recent Los Angeles Times analysis of teachers' performance based on their effectiveness in raising student test scores.

With students everywhere being tested annually for academic progress, it may not be a surprise that the data would eventually be used to evaluate the effectiveness of their teachers.

Michelle A. Rhee, the schools chancellor in Washington, fired about 25 teachers this summer based in part on their poor ratings from a "value-added" analysis of scores -- an increasingly popular and controversial method of rating teacher performance.

The Los Angeles Times recently published value-added ratings for 6,000 third-, fourth- and fifth-grade teachers based on students' English and math test scores over seven years. The analysis looks at individual students' past test performance and projects how they should do the next year. The difference between the child's actual and projected results is the estimated "value" that the teacher added during the year.

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Too Unreliable

New York Times
September 6, 2010
by Linda Darling Hammond

Linda Darling-Hammond is the Charles E. Ducommon Professor of Education at Stanford University where she co-directs the Stanford Center on Opportunity Policy in Education. She was founding director of the National Commission on Teaching and America's Future, and she led President Obama's education policy transition team.

Teacher evaluation was a fly-by operation when I was a high school English teacher 30 years ago, and it has improved little in most districts since. So I understand why there is such enthusiasm for evaluating teachers based on their students' test score gains, now that such data are available.

Evaluating and rewarding teachers primarily on the basis of state test score gains creates disincentives for teachers to take on struggling students.

Unfortunately, as useful as new value-added assessments are for large-scale research, studies repeatedly show that these measures are highly unstable for individual teachers. Among teachers who rank lowest in one year, fewer than a third remain at the bottom the next year, while just as many move to the top half. The top rankings are equally unstable. In fact, less than 20 percent of the variance in teachers' effectiveness ratings is predicted by their ratings the year before. This is why the National Research Council has said that this evaluation system "should not be used to make operational decisions because such estimates are far too unstable to be considered fair or reliable."

The reasons are simple. Test score gains are caused by many variables in addition to the teacher: students' learning and language background, attendance, supports at home, previous and current teachers, tutors, curriculum materials, class sizes and other school resources. Out-of-school time matters too. Summer learning loss accounts for more than half the achievement differential between high- and low-income students. Thus, researchers have found that the very same teacher looks more "effective" when she is teaching more advantaged students -- and less effective when she teaches more students who are low-income, new English learners, or who have special education needs.

Tragically, evaluating and rewarding teachers primarily on the basis of state test score gains creates disincentives for teachers to take on struggling students, just as accountability systems that rate doctors on their patients' mortality rates have caused surgeons to turn away patients who are very ill. While scores may play a role in teacher evaluation, they need to be viewed in context, along with other evidence of the teacher's practice.

Better systems exist -- like the career ladder evaluations in Denver and Rochester, the Teacher Advancement Program and the rigorous performance assessments used for National Board Certification, all of which link evidence of student learning to what teachers do in teaching curriculum to specific students. These systems also help teachers improve their practice -- accomplishing what evaluation, ultimately, should be designed to do.

 

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review: a good teacher in every classroom

A Good Teacher in Every Classroom: Preparing the Highly Qualified Teachers Our Children Deserve (2005, Jossey Bass) is the work of a blue-ribbon commission sponsored by the National Academy of Education to identify the core concepts and central pedagogies needed to create effective teacher education programs. The book also recommends policy changes to support effective programs. Edited by Linda Darling-Hammond and Joan Baratz-Snowden, the book recently received high praise in a review in the January edition of Education Review. Author Hailing Wu notes that, "A Good Teacher in Every Classroom seems destined to be highly influential." Read the review. Learn more about the book.