Education Endowment Foundation: Wechsler Individual Achievement Test – Third UK Edition

SubscalesⓘList of subscales (if applicable)

8 composite scores: (1) Oral Language, (2) Total Reading, (3) Basic Reading, (4) Reading Comprehension and Fluency, (5) Written Expression, (6) Mathematics, (7) Maths Fluency, (8) Total Achievement. 16 subtests: listening comprehension, oral expression, early reading skills, word reading, pseudoword decoding, reading comprehension, oral reading fluency, alphabet writing fluency, spelling, sentence composition, essay composition, maths problem solving, numeracy, maths fluency (addition, subtraction, multiplication).

Publisher

Pearson Clinical

Test source

https://www.pearsonclinical.co.uk/Psychology/ChildCognitionNeuropsychologyandLanguage/ChildAchievementMeasures/wiat-iii/wechsler-individual-achievement-test-third-uk-edition-wiat-iii-uk.aspx

Guidelines available?ⓘAdministration guidelines available to the review team

Yes

Norm-referenced scores

Yes

Age rangeⓘSpecific population and age range that publisher states the test is intended/​suitable for. 

4 – 25;11 years

Key Stage

Key Stage 1, Key Stage 2, Key Stage 3, Key Stage 4, Key Stage 5

UK standardisation sample

Yes

Publication date

2017

Re-norming date

N/​a

Are additional versions available?

WIAT-IIIUK (reviewed here) is a significant revision of WIAT-IIUK, including updated norms, new subtests, revised subtests with new items. Based on WIAT-III (US version). See also WIAT-IIIUK‑T.

Can subtests be administered in isolation?

Yes (note that some subtests cover specific age ranges).

Administration Group Size

Individual

Administration duration

Dependent on many factors. Administration times for each subtest by age and ability is presented on p12 of examiner’s manual. Total achievement composite 30 minutes – 60 minutes for younger children, 1.5 – 2 hours for older children/​adults. Few subtests should take >15 minutes to administer.

Description of materials needed to administer test

Materials included in the test kit: examiner’s manual (once familiar with procedures, the manual states that the examiner will not need to use the manual during administration); simulus book; oral reading fluency booklet; word card; pseudoword card; record form; response booklet; scoring workbook; audio files (on USB flashdrive). Other recommended materials: clipboard; stopwatch/​watch with second hand; audio recorder; audio player with external speakers; blank paper (blank/​lined depending on subtests being administered); pencils with and without rubbers.

Any special testing conditions?

Well lit, quiet environment free from disruptions and interruptions. 4 – 8 year olds should not have alphabet displayed in the room.

Is any prior knowledge/training/profession accreditation required for administration?

Yes

Is administration scripted?

(See p7 of Examiner’s Manual.) Chartered and research psychologists who are involved in psychological or educational testing and who have training in the use of individually administered assessment instruments are qualified to administer and interpret the WIAT-IIIUK. In all cases, examiners should have training in the fundamental principles of assessment procedures, including how to establish and maintain rapport, elicit optimum performance, follow standardised administration procedures, understand psychometric statistics, score and interpret tests, and maintain test security. The examiner should have experience in testing students whose ages, linguistic backgrounds, clinical, cultural, and educational histories are similar to those of the students tested with the WIAT-IIIUK. Specialist teachers who hold suitable qualifications can administer the subtests and score the responses under the supervision of a chartered or research psychologist. Only individuals who have recieved professional training in educational or psychological assessment should interpret the results of the WIAT-IIIUK. These user qualifications are consistent with the guidelines set forth in the Standards for Educational and Psychological Testing (Standards; American Educational Research Association [AERA], American Psychological Association, & National Council on Measurement in Education, 1999), and the International Guidelines for Test Use: Version 2000 (International Test Comission [ITC], 2000).

Rating Construct

Does it reflect the multidimensionality of the subject?

Generic literacy and generic maths (with specific subtests)

Construct validity comments (and reference for source)

Good detail about face validity for use for diagnostic purposes. Adaptations needed for Anglicisation from WIAT-III described in detail to the examiner’s manual and the UK scoring and normative manual. Construct validity is supported by moderate-strong intercorrelations between subtest age-based standard scores (.37 – .99), as well as appropriate correlations with previous versions of the WIAT. 79 children aged 6;2 – 16;10 completed WIAT-IIIUK and WIAT-IIUK with a testing interval of 14 – 49 days. Correlations were high or moderate for similar subtests (word reading .81; spelling .83) and lower for dissimilar subtests (word reading and numerical operations .28). The US version also shows good evidence of construct validity through correlations and discrepancy analyses with other measures (e.g. WPPSI-IV, WAIS-IV) and these findings are likely to transfer to the UK edition. See UK Scoring and Normative Manual for further detail. Evidence of contrasted group validity would have further supported diagnostic use, however would not be possible from the standardisation sample due to the nature of exclusionary criteria and stratification in sampling.

Rating Reliability

Summarise available comparisons

The UK scoring and normative manual indicates good reliability. Good-excellent internal consistency (coefficients .81 – .97; SEM 1.5 – 8.35) (presented by age group and overall for each subtest). 95% confidence intervals 3 – 16; 90% confidence intervals 2 – 13 (presented by age group and subtest). Test-retest reliability and inter-rater reliability are not reported in the UK version of the test. However, other measures of validity are available that were established on the WIAT-III US standaridsation, which are likely to be somewhat transferable, but here we limit to discussion of the UK studies.

Sources

Wechsler, D. (2017). Wechsler Individual Achievement Test – Third UK Edition. Examiner’s Manual. London, UK: Pearson Assessment. Breaux, K. C. (2017). Wechsler Individual Achievement Test – Third Edition. Technical Manual With Adult Norms. Bloomington, MN, USA: Pearson Clinical Assessment/​PsychCorp. Pearson Development Team (2017). Weschler Individual Achievement Test – Third UK Edition. UK Scoring and Normative Manual. London, UK: Pearson Assessment.