Fine Print: Overview of Measures for Tracking ‘Growth’

Controversy centers on using student achievement to help evaluate teachers

What it is: The State Department of Education last week posted two-page explainers for its proposed measures for student achievement in teacher evaluations, the “student growth percentile” (SGP) and the “student growth objective” (SGO).

What it means: The Christie administration is pushing hard to sell the new measures as a central piece of the new evaluation system, with public events across the state to explain how the process will work. With districts facing a deadline of next fall to have the system in place, the student achievement piece and particularly the SGP measures that work on state tests scores have by far been the most controversial part of the evaluation system.

SGP in one paragraph: The “student growth percentile” is a measure that looks at how much a particular teacher’s students have “grown” over the course of a year, using results of state test scores. Each student is compared to other students of comparable achievement levels across the state, and is placed in a percentile of the total. Each teacher then is given a median SGP of all his or her students. Under the administration’s new guidelines, that median SGP is worth 35 percent of a teacher’s overall evaluation.

SGO in one paragraph: The “student growth objective” is a second measure that will look at student achievement beyond state test scores. Since only about one-fifth of teachers have students taking the state’s tests, the SGO will be the only achievement measure for the bulk of teachers. It will be a set of specific learning goals set by each teacher and their supervisors, using other standardized tests or tests developed by the schools themselves. For all teachers, the SGOs will represent 15 percent of the evaluation.

What’s the controversy? The use of SGPs especially have drawn the brunt of the questions from teachers, administrators, unions and at least some researchers, who all question the validity of the scores as a valid measure of teacher effectiveness. With the scores presenting as much as one-third of a teacher’s evaluation, the stakes are pretty high.

New academic paper: One of the most outspoken critics has been Bruce Baker, a professor and researcher at Rutgers’ Graduate School of Education. He and two other researchers recently published a paper questioning the practice, titled “The Legal Consequences of Mandating High Stakes Decisions Based on Low Quality Information: Teacher Evaluation in the Race-to-the-Top Era.” It outlines the teacher evaluation systems being adopted nationwide and questions the use of SGP, specifically, saying the percentile measures is not designed to gauge teacher effectiveness and “thus have no place” in determining especially a teacher’s job fate.

The state’s response: The Christie administration cites its own research to back up its plans, the most favored being the recent Measures of Effective Teaching (MET) project funded by the Gates Foundation, which tracked 3,000 teachers over three years and found that student achievement measures in general are a critical component in determining a teacher’s effectiveness.

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