Will EVAAS make Wake schools better? Part One

Tuesday, May 31, 2011

By Bryan LeClaire • May 23rd, 2011 • Category: News, School board
Editor’s Note: In this two-part series, the Record examines the teacher evaluation system in Wake County. In Part One, we answer the question, what is EVAAS? In Part Two we will look at the debate around the program.

Last week, the Wake County Board of Education learned that the district’s most effective teachers are not teaching its lowest-performing students.

Assistant Superintendent for Evaluation and Research David Holdzkom presented board members with several maps showing the distribution of high-performing, National Board-certified and masters degreed teachers across the county.

The maps showed that high-performing teachers were concentrated in more affluent areas, while low-performing students clustered in less wealthy sections of the county.

The reasons for this discrepancy are unclear.

“How do we get those kids in front of those teachers?” said board member John Tedesco, chair of the Economically Disadvantaged Student Task Force.

In a district where the student assignment plan is up in the air, the question begs another:

How does the Wake County Public School System distinguish good teachers and students from the rest?


The Wake County Public School System uses the Education Value-Added Assessment System, or EVAAS, to rate its teachers.

EVAAS is a computer program owned by SAS Institute — a Cary-based, privately-held corporation that develops and sells specialized software for a variety of industries, from education to casinos to oil and gas.

Last November, the Wake County Board of Education voted 5-4 along party lines to dispense with the district’s long-used internal Effectiveness Index in favor of EVAAS.

EVAAS attempts to measure how well students perform in school from year to year. The program tracks student data at the classroom level, making it a tool for administrators to evaluate teachers.

But teachers unions and educational researchers around the country have critiqued EVAAS and other value-added systems across the country for years, raising a host of concerns, including their unreliability and a lack of data to support their widespread adoption.

North Carolina’s Department of Public Instruction, or DPI, has purchased a yearly EVAAS subscription from SAS and made the program available for free to all districts in the state since the 2007-08 school year. DPI spent almost $2 million on EVAAS this fiscal year.

How Does EVAAS Work?

The Wake County school system dumps into EVAAS all available end-of-grade (EOG) and end-of-course (EOC) testing data for every student. Based on past test performance, EVAAS establishes a predicted score for each student.

If a student earns exactly the score that EVAAS predicts, then the student achieved no growth that year. Scores below or above the predicted score determine whether the student achieved positive or negative growth.

EVAAS also averages the predicted score for all students assigned to an individual teacher. If that teacher’s students score exactly the predicted average, then EVAAS considers the teacher to have had no effect on the students. Average scores earned above or below the predicted average indicate a positive or negative effect on the students.

But teachers who are “effective” or even “highly effective” by this measure may not be “high-performing.”

That’s because teachers who are “high-performing” must have students who achieved growth above the average for all students in the state.

In other words, EVAAS compares all teachers in North Carolina to every other teacher in the state. In such a calculation, there will always be winners and losers. No matter how high educators push the average, some teachers will always be at or below the average.

While it is mathematically possible for all students in Wake County to achieve growth above the state average, a larger percentage of students — and teachers — in other districts would then have to perform at or below average.

The reverse is also true. The better other school districts do in EVAAS, the larger the number of Wake County teachers that would be considered at or below average.

This dynamic comes into play in the competition for federal Race to the Top funds and could affect any future merit pay system based on EVAAS ratings.

In addition, EVAAS ratings can be part of a teacher’s evaluation.



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