Texas Studies Suggest Test Design Flaw in TAKS - NYTimes.com - 0 views
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Jeff Bernstein on 30 Jul 12Now, in studies that threaten to shake the foundation of high-stakes test-based accountability, Mr. Stroup and two other researchers said they believe they have found the reason: a glitch embedded in the DNA of the state exams that, as a result of a statistical method used to assemble them, suggests they are virtually useless at measuring the effects of classroom instruction. Pearson, which has a five-year, $468 million contract to create the state's tests through 2015, uses "item response theory" to devise standardized exams, as other testing companies do. Using I.R.T., developers select questions based on a model that correlates students' ability with the probability that they will get a question right. That produces a test that Mr. Stroup said is more sensitive to how it ranks students than to measuring what they have learned.