OP-ED | Statistics and Liars
California’s teacher tenure laws were invalidated recently by Superior Court Judge Rolf Treu because the “statutes made it so onerous to fire bad teachers that they all but guaranteed needy kids would be stuck in classrooms with incompetent instructors.”
We’ve all heard “bad teacher” stories before. Critics often use the “bad teacher” scenario as Exhibit 1 in the Case Against Public Schools. Unfortunately, this focus on “bad teachers” and the tenure laws that supposedly prevent their dismissal have become a smokescreen for an even bigger problem: the blind worship of educational statistics.
Treu, for example, reinforced his decision by quoting the expert-witness account of Arizona State University professor David Berliner who testified that “1 to 3 percent of California teachers are grossly ineffective. Given that the evidence showed roughly 275,000 active teachers in the state, the extrapolated number of grossly ineffective teachers ranges from 2,750 to 8,250.”
Sounds horrific. It also sounds imprecise. What’s the source of these statistics?
“I pulled that out of thin air,” said Berliner. “There’s no data on that. Just a ballpark estimate, based on my visiting lots and lots of classrooms.”
Lots and lots of classrooms?
Welcome to the world of educational statistics.
Berliner is actually a critic of another notorious statistical contrivance in education, value-added models (VAMs): “These models require data that track individual students’ academic growth over several years and different subjects in order to estimate the contributions that teachers make to that growth.”
“[R]esearch suggests that teachers don’t really control much of how their pupils perform on exams,” writes Berliner. “According to the American Statistical Association (ASA), they influence anywhere between 1 percent and 14 percent of the variation in students’ scores. As result, teachers often don’t deliver the same results year after year.”
ASA’s official statement warns school districts that VAMs are “generally based on standardized test scores, and do not directly measure potential teacher contributions toward other student outcomes.” That is, “VAMs typically measure correlation, not causation: Effects — positive or negative — attributed to a teacher may actually be caused by other factors that are not captured in the model.”
Despite such criticism, value-added models are used in teacher-evaluation models because they provide a seemingly exact measurement of teacher performance. What’s not to like about specific numbers attached to specific teachers in order to categorize them as “good,” “bad,” or “grossly ineffective”?
I’ve explored this topic before, noting how the current fetish for educational statistics has its roots in “scientific management,” the system of workplace efficiency established by Frederick Winslow Taylor in the early 20th century through “time-and-motion studies.”
Taylor’s ideas spread beyond the industrial workplace and gained a sort of “worldview status” by which devotees could neatly measure, label, and evaluate anything and everything.
Neil Postman explained in his book, Technopoly: The Surrender of Culture to Technology, that Taylorism frames the world around assumptions: “These include the beliefs that the primary, if not only, goal of human labor and thought is efficiency; that technical calculation is in all respects superior to human judgment; that in fact human judgment cannot be trusted, because it is plagued by laxity, ambiguity, and unnecessary complexity; [and] that subjectivity is an obstacle to clear thinking.”
In short, Taylorism suggests “what cannot be measured either does not exist or is of no value; and that the affairs of citizens are best guided and conducted by experts,” according to Postman.
If teachers cannot be measured, therefore, they are of no value. Thus, we must somehow measure them to demarcate “valuable teachers” and “bad teachers.”
My own worldview is not so orderly. Where others see numbers and percentages attached to teacher classifications, I see ambiguity and manipulation. We’re talking about human beings, after all — not robots.
In my classroom, I often use music to enhance lessons. Billy Joel’s “Shades of Grey” seems fitting here:
“Now with the wisdom of years, I try to reason things out,
And the only people I fear are those who never have doubts.
Save us all from arrogant men, and all the causes they’re for.
I won’t be righteous again.
I’m not that sure anymore.”
Perhaps Judge Rolf Treu is confident enough with statistics “pulled out of thin air” to help him make a decision affecting millions of people.
Me? I’m not that sure anymore.