Andy Hall:

The analysis of data from 27 elementary schools and 11 middle schools is based on scores from the Wisconsin Knowledge and Concepts Examination (WKCE), a state test required by the federal No Child Left Behind law.
Madison is the second Wisconsin district, after Milwaukee, to make a major push toward value-added systems, which are gaining support nationally as an improved way of measuring school performance.
Advocates say it’s better to track specific students’ gains over time than the current system, which holds schools accountable for how many students at a single point in time are rated proficient on state tests.
“This is very important,” Madison schools Superintendent Daniel Nerad said. “We think it’s a particularly fair way … because it’s looking at the growth in that school and ascertaining the influence that the school is having on that outcome.”
The findings will be used to pinpoint effective teaching methods and classroom design strategies, officials said. But they won’t be used to evaluate teachers: That’s forbidden by state law.
The district paid about $60,000 for the study.

Much more on “Value Added Assessment” here.
Ironically, the Wisconsin Department of Public Instruction stated the following:

“… The WKCE is a large-scale assessment designed to provide a snapshot of how well a district or school is doing at helping all students reach proficiency on state standards, with a focus on school and district-level accountability. A large-scale, summative assessment such as the WKCE is not designed to provide diagnostic information about individual students. Those assessments are best done at the local level, where immediate results can be obtained. Schools should not rely on only WKCE data to gauge progress of individual students or to determine effectiveness of programs or curriculum.”

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