The most telling aspect of Charleston County School District’s announcement about holding teachers accountable for student test scores may be in the second paragraph of Paul Bowers’s coverage: “District leaders say they don’t want to fire anyone — particularly not in the midst of a statewide teacher shortage that’s only getting worse.”
While it appears some are aware of the unintended consequences of new education policy, we must be concerned that such awareness has not helped better inform this recent decision to move forward with using value-added methods (VAM) in teacher evaluations.
Early research warned and current studies confirm that VAM fails to fulfill political promises, but also feeds existing problems. This pattern has been seen with school choice increasing segregation, exit exams causing higher drop-out rates, and high-stakes tests driving teaching to the test, asking far less of students.
First, we should acknowledge the flawed logic driving the use of VAM to increase teacher accountability. The recent concern about teacher quality is grounded in several false assumptions.
One is the “bad” teacher myth strongly associated with the stereotypical unionized teacher as portrayed in “Waiting for Superman.” However, across the U.S., teachers in unionized states produce students with higher test scores than teachers in non-union (called right-to-work) states such as South Carolina. The problem with associating teacher quality and low student outcomes with union protection is that student test scores are more powerfully associated with poverty than any other factor. This leads to the other false assumption that teacher quality is the most or one of the most important causes of student learning. In fact, teacher quality accounts for only about 10-15 percent of standardized test scores, the basis of VAM, while out-of-school factors remain the greatest influence, at 60 percent.
A final assumption is that using test data to evaluate teachers is objective and valid, and thus fair. Yet, many teachers are in content areas without standardized tests, and then, ironically, making any set of data high-stakes causes that data to be less credible (see Campbell’s Law).
Student test scores are poor evidence about teacher quality, and making those scores central to evaluating teachers is guaranteed to further erode that evidence’s usefulness and the process.
Matthew Di Carlo, blogging for the Albert Shanker Institute, details the unintended consequences of VAM as implemented in Houston.
While assessing the Houston teacher evaluation system, Julie Berry Cullen, Cory Koedel, and Eric Parsons discovered that teachers identified as weaker by their student test scores were already leaving at high rates before the new system was implemented in order to identify weak teachers. In other words, Houston adopted a policy without investigating whether or not teacher quality was the key problem, without acknowledging that with high teacher attrition among so-called weaker teachers, schools were not achieving in ways they envisioned.
Here is one powerful lesson of education reform: Do not adopt a policy until you gather evidence of the problems, and assumptions about those problems are not enough.
After Houston adopted VAM-based evaluation of teacher, as Di Carlo explains, teachers identified by test scores as weak were even more likely to leave, but, on the other hand, all exits increased under the new evaluations — including among teachers who were rated as average and high performers. The extent to which this spike is attributable to the new evaluation system per se is unclear, but it served to “dilute” the impact on student achievement of the increase in exits among low performers.
Historically and currently, Charleston has a teacher problem, yet Houston is a powerful example of how VAM is not the solution to those problems. The remaining challenge is recruiting and maintaining experienced and certified teachers in the schools that serve the most vulnerable students from high-poverty homes and communities.The new policy linking teacher evaluations with student test scores will not address those challenges, and we can expect it will actually increase challenges to recruit new teachers and stem teacher attrition.
By adopting VAM and investing in a critically discredited system, EVAAS, Charleston County School District is late to a very bad party. The students and community would be better served by making sure we know what the teacher quality problems are and then seeking ways to address those instead of choosing political expediency and wasting tax dollars on policies and programs already shown to fail.
P.L. Thomas is a professor at Furman University.