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This method combines Automated Test Assembly (ATA) with content experts' input to create optimal test forms meeting psychometric targets and content constraints. Genetic Algorithm optimizes item selection. Improve feedback and reduce distance from target TIF and TCC. Useful for ELA and Math tests.
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A Method for Cooperative Test Assembly for Large-Scale Assessment Jon Brasfield Wonsuk Kim Matt Finkelman Louis Roussos
Automated Test Assembly (ATA) • Foundation: Birnbaum (1968) suggested using the additive relationship between Item Information and the TIF to assemble a test • General outline, not actual method • Computers weren’t powerful enough
ATA Literature • Lots of ATA literature • Doesn’t involve content experts • Need for a method that combines the benefits of ATA with the substantive contributions of content experts • More practical
Outline of Project • Use ATA to improve the feedback loop inherent in Form Pulling • Will automatically create forms that meet psychometric targets (TCC and TIF) and content constraints • ELA Test – Create form options • Math Test – Create initial form
ELA Test • Create detailed feedback to give to test developers • Based on initial form – constructed primarily on content concerns • Developers create initial form, denote “definite” and “maybe” items • Content Constraints: item type, passage association, standard addressed • Psychometric constraint: Target TCC tolerance
ELA test – Our process Item Pool 5,000 Times Test Form
ELA Test – Our process Item Pool 5,000 times Test Form
ELA Test – Our Process • Must meet tolerance on Target TCC
ELA Test – Best Result • Used Genetic Algorithm • Based on theories of evolution and natural selection • Originally discussed in Computer science (Holland, 1968) • Potential solutions “evolve” toward a target, or optimum solution • Require 3 components: Decision variable, objective function, and constraints
ELA Test – best result • Our objective function: minimize total distance from Target TIF • A set of items that meets the constraints is selected (a “parent”) • For each parent, each item is temporarily replaced (one at a time) with a random item from the pool • Process is repeated, selecting the fittest sets each time
Bottom Line: ELA Test • All forms found exhibited a lower summed absolute distance from the target than the initial form or the actual form Target TIF Improvement
Math Test • Initial form provided by psychometrics: Optimize statistics while staying within content constraints • Constraints include Item type, strand, standard, age of item • Only one form is needed, so GA is used
Math Test – Bottom Line TTIF Distance Reduction of 89.17% TTCC Distance Reduction of 91.68%
Summary • ELA Test – Content Experts can provide an initial form, psychometrics can give multiple statistically sound options while keeping important items • Math Test – Can easily construct a “first draft” form that is very close to psychometric targets and meets content constraints
Future research • Qualitative feedback from content experts, DOE • Use Genetic Algorithm to develop multiple forms