Psychometric evaluation of the Norwegian version of the Wechsler Abbreviated Scale of Intelligence (WASI)
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Key message
The Norwegian Knowledge Centre for the Health Services was commissioned by the Norwegian Directorate of Health to undertake a review and assessment of Norwegian research on psychometric properties of all psychiatric measures used in Norway.
Description WASI
Wechsler Abbreviated Scale of Intelligence (WASI) is a shortened version of a full intelligence test and gives an estimate of intelligence. WASI is therefore suitable for screening purpose where a full assessment of cognitive functioning is not appropriate. The test was published in English in 1999 and was published in Norwegian commercial edition from 2007 (copyright Pearson Assessment). Estimated time of administration is about 30 minutes. The test has American standards covering the age range from 6 to 89 years. The required competence for the use and interpretation of WASI is training as a psychologist, master in education or special education, with specialized educational and school psychology as well as general training in test use.
Method
We developed a search strategy for a systematic literature search. It was applied in medical and psychological databases for studies using WASI in Norwegian adult populations. The search was conducted in December 2013, and two researchers have independently identified references considered relevant to the inclusion criteria, and extracted relevant data.
Results
We included 22 studies. These studies formed the basis for the Norwegian psychometric evaluation together with the English and Norwegian edition of the test manual.
Conclusion
The construct and convergent validity of WASI is supported by the reviewed studies. However, there is uncertainty as to the interpretation of the scores derived from the test because they are based on American standards from the mid 90s. Norms for Norway have not been constructed nor is a comprehensive study of the use of the American norms in a Norwegian setting conducted. Assessment of cognitive functioning based on the American norms may lead to an overestimation of test participant’s ability level.