Putting Teachers to the Test
Every day in grade 11 physics class, I would sit down, write the date at the top of a new notebook page, and then in small letters "40." "40" was the number of minutes left in class. Ten numb minutes later, I would cross out the "40" and replace it with "30," and an eon later, I'd write "20." I'd check my watch, stare out the window, and write a note to a friend before "10," and at "5," I'd start rudely packing up my books. Not surprisingly, the lowest mark on my high school transcript is physics.
It was obvious to my adolescent peers and to me, as it was no doubt obvious to our parents and the school principal, that this physics teacher had no business being in a classroom. Over his long career, this man had significantly contributed to making a couple of thousand young people hate physics, and had done his part to put them off learning altogether.
We all know intuitively the difference between a good and a bad teacher. I'm sure that, without much thought, each of you reading this article can pinpoint one teacher who, in the course of a year, gave you more insight, excitement, and education than most others could give you in five. You'll also remember teachers who set you back a couple of years by crushing your self confidence or, in my case with physics, killing any nascent interest you might have had in the subject. If you're like me, you still bear a small grudge towards these people for inflicting upon you boredom or humiliation.
But is it possible to ascertain objectively the difference between a good and a bad teacher? And what policies would be most likely to improve the quality of teaching? For generations, governments, unions, and faculties of education across North America have ignored the first question, but have worked to raise teaching standards using a regulatory approach. They have raised the hurdles between a would-be teacher and a classroom (degrees, certification, endless courses in pedagogy, and seniority) and concerned themselves not with what comes out of the classroom at the end of the year, but with what goes into it at the beginning. Regulating inputs is both expensive and inefficient. It has contributed to a dearth of bright, able applicants to the teaching profession, and failed to raise the standard of student achievement or to reduce the numbers of students dropping out of school without skills or qualifications.1 But another approach commanding attention in the United States is more promising.
The new approach begins by tackling the first question - how do you know a good teacher from a bad one? - head on by measuring teacher output. William Sanders at the University of Tennessee has developed a sophisticated and compelling system for doing just this, one that has been used in Tennessee for nearly a decade and is gaining respect from further afield. His Tennessee Value-Added Assessment System (TVAAS) calculates the "value" added by a teacher over the course of a year to a student's work. Students are tested at the beginning of the school year, and then again at the end, and teachers are graded based on the progress their students make over the course of the year.
Since 1992, Tennessee has required that value-added assessment be conducted annually in every elementary classroom in the state. Sanders, Director of the University of Tennessee Value-Added Research and Assessment Center, has used the data to calculate the impact that teachers have on their students' learning. After analyzing six million student records and more than 30,000 teachers, he has quantified the difference between a good teacher and a bad one. He has found that a single, ineffective teacher can impede a student's progress for at least four years.2
Not surprisingly, children of equal academic ability from similar family backgrounds have startlingly different results if caught in a sequence of good or bad teachers. Dr. Sanders found "if we were to look at two kids who left second grade with the same achievement level, and one, by fate, caught for each of the next three years a teacher we had identified as being in the top 20th percentile, that kid scored on average at the 96th percentile on the fifth grade math test. But if the other kid caught for three years a teacher at the bottom, he scored in the 44th percentile... Teacher effectiveness is 10 to 20 times as significant as other things."3
Value-Added Assessment is fair to teachers because it considers only the achievement gains made in the course of the year. It does not, like most other standardized-test accountability systems, compare students to an average or prescribed standard, which inevitably gives credit to teachers whose students entered their classrooms with greater ability, or penalizes those whose students began the year behind. Rather, value-added assessment levels the playing field for teachers and schools. In doing so it removes the objection put forward so often against standardized tests: that they fail to take into account a student's background. Value-added assessment excludes the influence of all pre-existing differences among students, including race, socio-economic status, intelligence and previous learning.4
In Tennessee, each teacher's performance is reported to the school and to the teacher herself. School districts that have chosen to ignore the information have stagnant or declining results while those that have used the data to work with teachers and schools are showing measurable progress.5
Any policy that promises to improve teacher quality must incorporate two elements. First, it must include measurement, not only of student performance in absolute terms, but also of the difference an individual teacher makes to the progress of his students. Second, it must create an incentive for schools to improve. Principals must have the freedom to hire the teachers they believe will do the best job for their students, and an incentive to help their staff improve their performance.
This is the approach that is sanctioned by a growing number of state officials, prominent education analysts, and veteran practitioners in the United States. Canadian policy makers would do well to take notes. "The Teachers We Need and How to Get More of Them: A Manifesto," signed by dozens of prominent educators and released last April by the Thomas B. Fordham Foundation, concludes that "instead of requiring a long list of courses and degrees, test future teachers for their knowledge and skills. Allow principals to hire the teachers they need. Focus relentlessly on results, on whether students are learning. This strategy, we are confident, will produce a larger supply of able teachers and will tie judgments about their fitness and performance to success in the classroom, not to process or impression."6
Who knows, if the Toronto Public School Board had practised this strategy 15 years ago, perhaps I'd be a physicist today. Perhaps I'd have to be! There would certainly be less work for education reformers.
Notes
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Claudia Rebanks Hepburn (1999), The Case for School Choice: Models from the United States, New Zealand, Sweden and Denmark, Critical Issues Bulletin (September), Vancouver: The Fraser Institute, pp. 4-5.
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Marilyn Marks (2000), "The Teacher Factor," New York Times, Education Life Supplement, January 9, 2000.
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Quoted in an interview by Marilyn Marks.
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J.E. Stone (1999), "What Is Value-Added Assessment and Why Do We Need It?" Education Consumers ClearingHouse. Digital document: http://education-consumers.com/TVAAS-web.htm (February 17, 2000).
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Marilyn Marks (2000).
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Thomas B. Fordham Foundation (1999), "The Teachers We Need and How to Get More of Them: A Manifesto," p. 2. Digital document: http://www.edexcellence.net/library/teacher.html (February 18, 2000).
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