Investigating the National Adult Reading Test (NART-2) and Wechsler Test of Adult Reading Test (WTAR) in predicting Wechsler Abbreviated Scale of Intelligence – Second edition (WASI-II) scores in an Australian sample

ABSTRACT

Objective: The NART-2 and WTAR are used to estimate premorbid intellectual functioning. There are concerns about their accuracy. Our aim was to develop models predicting WASI-II scores from the NART-2 and WTAR variables and evaluate their accuracy within an Australian sample.

Method: The sample included 145 adults aged 18.91 to 70.64 years (M = 34.70, SD = 13.30), of which 78 were female. Analyses examined the reliability of the word reading tasks and estimated WASI-II sores with multiple linear regression. Comparison of estimated scores were made with actual WASI-II scores.

Results: WASI-II scores were moderately related to word reading tasks (r = .33 to.51, p < .01) and weakly related to age, years of education, and occupation. Models were identified for the four WASI-II index scores (with R2 = .20 to .36) and their accuracy checked. 24%-48%, 61%-73% and 80%-88% were correctly estimated within five, 10 and 15 points, respectively.

Conclusions: Models for predicting WASI-II scores from the NART-2 and WTAR and demographic variables had adequate strength and accuracy. However, they were likely to be limited to those with FSIQ>79. Further development of word reading tasks for the prediction of premorbid intellectual functioning in the contemporary Australian context is warranted.

Key Points

What is already known about this topic:

• (1) The estimation of premorbid intellectual functioning is important in cognitive assessment, for which tests such as the National Adult Reading Test (NART-2) and Wechsler Test of Adult Reading Test (WTAR) were developed.

• (2) Research has pointed to potential problems with using the ageing norms and predictive models of the NART-2 and WTAR and recent Australian research has presented new models for predicting current Wechsler Adult Intelligence Scale (WAIS-IV) scores.

• (3) No evaluation of the NART-2 or WTAR has examined the accuracy of these models in predicting the shorter Wechsler Abbreviated Scales of Intelligence – Second Edition (WASI-II) scores in the Australian context.

What this topic adds:

• (1) This study provides norms for the NART-2 and WTAR utilising Australian pronunciation rules, consistent with the Macquarie Dictionary.

• (2) Equations are presented for predicting WASI-II scores from NART-2 and WTAR scores and simple demographic variables, based on a healthy sample of Australian adults.

• (3) Evaluation of these predictive models shows they are likely to have adequate strength and accuracy, but were limited to predicting ability to within the low average range and above (FSIQ>79).

KEYWORDS:

• Cognitive assessment
• National Adult Reading Test (NART)
• premorbid intellectual functioning
• psychometric evaluation
• Wechsler Abbreviated Scale of Intelligence – Second edition (WASI-II)
• Wechsler Test of Adult Reading Test (WTAR)

Acknowledgments

We would like to express our gratitude and appreciation to the participants who volunteered for this study and to Catherine Richardson, Michael Magee, Michelle Vongdara and Maddison Lloyd who assisted with data collection and initial analyses, as part of their psychology student research experience.

Disclosure of potential conflicts of interest

No potential conflict of interest was reported by the author(s).

Additional information

Funding

This work was supported by the Charles Sturt University, Faculty of Arts [Faculty Research Compact Grant].