Psychometric Properties
- Internal consistency ranges from 0.80-0.98.
- Test-retest reliability ranges from 0.85-0.98.
WIAT–II has been empirically linked with the WISC–IV, the WPPSI–III, and the WAIS–III. These relationships provide valid discrepancy scores to allow comparisons between achievement and ability. The WIAT-II UK was standardised between 2003-2004 as part of the WISC-IV standardisation with 892 individuals aged 4-16years 11 months (US norms are available up to age 85). The UK project was conducted at City University by Professor John Rust and Professor Susan Golombok. The WAIT-II standardisation also includes several special group studies including those with learning difficulties, ADHD, emotional disturbance, hearing impairments, speech and language impairments and those who are classed as gifted.
The WIAT-III US was standardised on 3,000 students and adults aged 4-19:11. Linking studies were carried out with the WAIS-IV, WISC-IV, WPPSI-III, WMV, and DAS-II with correlations ranging from .60-.82. Special group studies include those with learning difficulties in reading, writing and math, expressive language disorder and mild intellectual difficulties.
Read more about this topic: Wechsler Individual Achievement Test
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“The reason why men enter into society, is the preservation of their property; and the end why they choose and authorize a legislative, is, that there may be laws made, and rules set, as guards and fences to the properties of all the members of the society: to limit the power, and moderate the dominion, of every part and member of the society.”
—John Locke (1632–1704)