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Test-Based Teacher Evaluation Earns F, Again

South Carolina is poised to link 40% of teacher evaluations to student test scores. Is that a colossal mistake?
 
 
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Teacher quality, including teacher evaluation and pay scales, is a growing national and state concern in education reform -- a trend that can be traced to, and remains reflected in, the Los Angeles Times' repeated publication of value-added models (VAM) of ranking teacher quality.

Catherine S. Durso’s National Education Policy Center review of VAM results calculated for and reported by the Los Angeles Times exposes that once again linking teacher quality to student test scores fails to identify fairly high-quality teachers. The body of evidence shows that test-based teacher evaluation is unstable and counter-productive to evaluating, paying and retaining teachers, explains Durso:
Many researchers have raised concerns regarding the use of value-added models (VAM) for teacher evaluation. Briefly, VAM do not provide guidance for improvement, are comparative rather than absolute measures, assess a small part of teacher’s responsibilities, force different kinds of teaching into one scale, do not produce consistent results for given teachers over time, and may not identify effects actually caused by the teachers.
Test-Based Teacher Evaluations: A Failed Solution without a Problem
 
These conclusions about VAM in California and throughout the country are powerful but ignored evidence in states across the U.S., including my home state of South Carolina, now poised to link 40 percent of teacher evaluations to student test scores -- policy as misguided as SC’s commitments to experimenting with students through expanding charter schools and hiring Teach for America (TFA) recruits.
 
And just as no solid evidence supports increasing faith in charter schools and TFA, test-based teacher evaluation should have no place in education and teacher quality reform in SC. Let’s consider the many reasons that addressing teacher quality through test scores is a waste of precious time and resources for any state at the expense of their students and teachers:
  • As noted above, the relatively new but growing body of evidence on the validity and reliability of test-based teacher evaluations reveals that data are unstable [1]; in other words, as the populations of students change or the school settings change, the rankings of the teachers fluctuate. Test-based teacher evaluation can be of value only if it can offer a stable message that a teacher is strong or weak. If that label isn’t predictive, it has no positive contribution to policy and personnel decisions.
     
  • In order to implement test-based teacher evaluation that shows student growth, SC will have to create and implement two tests per course for every teacher in the state and in every content area taught. Since there is no compelling evidence test-based teacher evaluation data are stable or valid, this investment in time and money is a catastrophic failure by our state leaders. How will we identify growth in music, P.E. and art, and how can we justify the costs associated with generating all of these tests?
     
  • Test-based teacher evaluations create a competitive environment in which teachers must choose between the welfare of their students and their own professional security as that becomes threatened by the outcomes of other teachers and their students. In effect, each teacher must seek to use her/his students against the outcomes of other teachers’ students for their own personal gain. Education is best served by a collaborative, not competitive, environment.
     
  • Test-based evaluations of teachers place far too much weight on flawed assumptions. First, high-stakes testing distorts how well any tests reflect student learning. Next, high-stakes testing decreases the quality of both teaching and learning since it encourages teaching to the test. Further, linking teacher evaluations to student outcomes confuses “high-quality teaching” with student test scores, although we have no way to insure that teacher quality is always positively correlated with those scores. And finally, test-based evaluations of teachers imply that student outcomes are or can be linked only to the teacher’s room that any student sits in when the test is administered. Here is the great failure of test-based evaluations of teachers: Data linked to a student are correlated with dozens of conditions (that cannot be controlled for) that distort any one teacher’s quality.
Claiming that teacher quality is central to education reform is a powerful and compelling message—although teacher quality is overshadowed by out-of-school factors. As I have noted about committing to charter schools, SC must stop pursuing solutions without identifying the primary problems, which include the inequity that creates poverty and the inequitable distribution of high-quality teachers.
 
Test-based reforms to teacher evaluation, pay and retention have no place at the education reform table in SC since there is no evidence it is needed or that it works. To pursue test-based teacher evaluation while the state continues to struggle economically and educationally is an inexcusable failure of state leadership.
 
[1] See the evidence compiled here.

P.L. Thomas is an associate professor of education at Furman University.