Value-Added Measures in Education: What Every Educator Needs to Know

Fewer topics in education arouse more controversy than value-added measures. There are disagreements about how value-added scores should be calculated. There are arguments about what value-added scores tell us about schools or teachers. There are differences of opinion about how value-added data should be used. The polemic received full public attention in August, 2010 when the LA Times published district teacher rankings based on individual teachers’ value-added scores, custom-calculated for the newspaper by statisticians at the Rand Corporation. Union representatives were aghast, teachers were appalled, parents were intrigued, students were amused, and academic scholars were either supportive or critical. The problem was that Doug Harris’s book Value-Added Measures in Education: What Every Educator Needs to Know had yet to be published, so the definitive resource for how best to assess the LA Times data was not available.

Harris faced one big challenge in writing this book: how to determine his prime audience. If his intended readers constitute “every educator,” as the title states, then Harris is addressing the kindergarten teacher as well as the university professor, the school superintendent and the teaching intern, the math coach and the undergraduate education major, the doctoral student and the educational researcher, teacher unionists, and education policy makers. The primary readership will determine how technically the author treats his subject matter. Too steeped in the niceties of statistics and he loses most teachers, too simplistic and the university readers are gone. The position he takes on the merits or not of value-added measures may alienate its detractors or its advocates. If he takes no position, then policy-makers will be disappointed.

So what does Doug Harris do? As a professor, Harris, one presumes, is used to presenting complicated information in a manner that is accessible to students with different levels of ability and background. As a researcher, he is familiar with the need to be objective, thorough, and focused on empirical evidence. Fortunately, Harris combines his experience from these dual roles well in the writing of this book. He covers the ground comprehensively, from a discussion of achievement tests and how to use them to measure student growth, to the calculation and use of value-added scores. He remains impartial throughout, showing us the potential benefits of value-added approaches over other measures for estimating teacher or school effectiveness, while also pointing out their shortcomings. He educates us in how to minimize the deficiencies and presents us with strategies for making the most of the information that value-added calculations can provide. He addresses misconceptions, highlights the advantages of value-added over other measures and suggests ways for using value-added information to improve teaching and learning. Value-added measures, we learn, can be used for professional development as well as for evaluation and accountability.

Harris demonstrates his points through the presentation of case study data from schools that belong to a hypothetical school district. This is not only a useful tool that yields data pictures, but a smart way to appeal to school administrators who spend much of their time looking at charts and graphs of test data and trying to determine whether their efforts have helped students advance, if their teachers are doing a satisfactory job, and how their schools measure up against those in other districts.

Harris projects his authorial voice to a lay audience. At least to those who, we assume, know little about the complex workings of value-added scores and the ins and outs of assessing student achievement. The topic is technical, and if he were trying to appeal primarily to other researchers in the field of value-added measurement he would lose the greater part of the titular population that includes “every educator.” In adopting a general approach, however, Harris runs the risk that his book will not be taken as a serious contribution to the field of academic scholarship on the topic. I think this is a risk well worth taking. While I’m not sure how many parents and teachers who pick up this book will continue reading it, I am convinced that it should be a required text for school administrators, policy makers, and undergraduate education classes.

It is interesting to read the Foreword, written by Randi Weingarten, the president of the American Federation of Teachers. While applauding Harris’s efforts to make a technical topic accessible to parents, teachers, and administrators, Weingarten’s comments otherwise emphasize the book’s treatment of the limitations, the inherent margin of error, and the general inadequacies of value-added measures. We know from her other writings that Weingarten is not a big fan of using value-added measures, at least in their current forms, for teacher evaluation. However, it is refreshing to see that she endorses this book and is clearly open to the possibilities of the value-added construct. In the same way, what makes Harris’s book so useful and trustworthy is that he is not telling us (as some other highly influential educators have done) to adopt or to reject value-added modeling as a means for assessing a teacher’s or a school’s contribution to student growth. Instead he presents, in a clear and objective manner, the inside workings, the strengths, the limitations, and the several potential uses of value-added measures as well as their possibilities for helping us improve our schools.

I doubt that the book will appeal to every educator. By representing a middle ground it will be dismissed by research experts, and seen as still too technical by some teachers. It is, however, a great resource for the largest proportion of educators, particularly education students and anyone whose duties involve interpreting student achievement data. It should be required reading for elected officials who make education policy. Let’s hope the word gets out that there is now a complete, readable, and objective book on value-added measures in education.