This editorial will appear in Wednesday’s print edition.
The timing couldn’t be better.
Just as Washington’s school districts are gearing up to adopt new teacher evaluation systems, along comes an authoritative mega-study that spells out how to get it right.
The project – funded by the Bill & Melinda Gates Foundation – is an exceptional piece of science.
The goal was to define measures that could consistently identify effective teachers. This is tough. Classes vary widely from year to year, some schools are loaded with disadvantaged students, and teaching itself is complex process.
Some have argued that no system can fairly and reliably sort out the better educators from those who need help. Public school systems have commonly relied on two crude measures, seniority and possession of a master’s degree, both notoriously inaccurate at identifying classroom stars.
The Measures of Effective Teaching study tracked a huge sample of teachers – 3,000 teachers – over three years.
The researchers found that three measures – student test performance, classroom observations and student surveys – accurately predicted which teachers would produce the most successful students.
This wasn’t just a case of the teachers looking good because they had more privileged or smarter classes. They also did well when students were randomly assigned to their classrooms.
The specific findings are important.
• Using two or three different qualified observers proved far more accurate at spotting classroom effectiveness than using just one – say, the principal. This isn’t because principals were biased against their teachers; if anything, they appeared to rate them more generously than do outside observers.
• Weighting the evaluation heavily toward test score improvement helped identify – no surprise – which teachers would best help students improve at standardized state tests. But that was the least reliable metric, and also the least connected to higher-order thinking skills.
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