Reports strongly suggest that most current teacher evaluations are largely a meaningless process, failing to identify the strongest and weakest teachers. The New Teacher Project's report, "Teacher Hiring, Assignment and Transfer in Chicago Public Schools (CPS)" (July2007) at: http://www.tntp.org/files/TNTPAnalysis-Chicago.pdf, found that the CPS teacher performance evaluation system at that time did not distinguish strong performers and was ineffective at identifying poor performers and dismissing them from Chicago schools. See also Brian Jacobs and Lars Lefgren, "When Principals Rate Teachers," Education Next (Spring 2006). Similar findings were reported for a larger sample in The New Teacher Project's The Widget Effect (2009) at: http://widgeteffect.org/
. See also MET Project (2010). Learning about teaching: Initial findings from the measures of effective teaching project
. Seattle, WA: Bill & Melinda Gates Foundation.
A Pacific Research Institute study found that in California, between 1990 and 1999, only 227 teacher dismissal cases reached the final phase of termination hearings. The authors write: "If all these cases occurred in one year, it would represent one-tenth of 1 percent of tenured teachers in the state. Yet, this number was spread out over an entire decade." In Los Angeles alone, over the same time period, only one teacher went through the dismissal process from start to finish. See Pamela A. Riley, et al., "Contract for Failure," Pacific Research Institute (2002).
That the vast majority of districts have no teachers deserving of an unsatisfactory rating does not seem to correlate with our knowledge of most professions that routinely have individuals in them who are not well suited to the job. Nor do these teacher ratings seem to correlate with school performance, suggesting teacher evaluations are not a meaningful measure of teacher effectiveness. For more information on the reliability of many evaluation systems, particularly the binary systems used by the vast majority of school districts, see S. Loeb et al, "Evaluating Teachers: The Important Role of Value-Added." The Brookings Brown Center Task Group on Teacher Quality (2010).
There is growing evidence suggesting that standards-based teacher evaluations that include multiple measures of teacher effectiveness—both objective and subjective measures—correlate with teacher improvement and student achievement. For example see T. Kane et al, "Evaluating Teacher Effectiveness." Education Next Vol 11 No. 3 (2011); E. Taylor and J. Tyler, "The Effect of Evaluation on Performance: Evidence from Longitudinal Student Achievement Data of Mid-Career Teachers." National Bureau of Economic Research (2011); as well as Herbert G. Heneman III, et al., "CPRE Policy Brief: Standards-based Teacher Evaluation as a Foundation for Knowledge- and Skill-based Pay," Consortium for Policy Research, 2006.