Issues in the educational, psychological assessment of visually impaired children: Test-retest reliability of the Williams Intelligence Test for Children with Defective Vision

The article discusses some problems confronting teachers and psychologists when making decisions as to how to use the currently available test procedures. It reports data gathered on three separate occasions on the performance of a group of blind and partially sighted children on the Williams Intelligence Test which is the only specialist IQ test standardized in the UK. Correlation co-efficients indicate that the test achieves very satisfactory levels of test-retest reliability. Attention is drawn to changes, including improvements, in individual scores over time that have implications for educational advisers. Some of these improvements are attributed to the widening of experiences in the physical exploration of the environment, in language opportunities, and in socialization that are due to the effects of good pre-school and early-school placements. Despite the test’s good reliability as revealed by this longitudinal study, it is suggested that the time has now come for the design and standardization of a new test incorporating current developments and thinking.