A psychometric evaluation was conducted on the Diagnostic Assessment Procedure (DAP), which evaluates the visual efficiency of legally blind persons with low vision. The DAP was administered twice to 112 legally blind students ages 5 to 20. Reliability coefficients showed that the DAP was internally consistent (KR-20 = .94) and accurate (test-retest, r = .96) to an extremely high degree. The hierarchical nature of the DAP and the validity of its content and construct are discussed.
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