Evaluation of the “Three Steps in Screening for Dyslexia” Assessment Protocol Designed for New Zealand Teachers

Abstract

Traditionally, the New Zealand Ministry of Education opposed the recognition of dyslexia. However, since 2007, the Ministry of Education’s position has started to change, evidenced by the development of a working definition. In 2021 the Ministry of Education released Three Steps in Screening for Dyslexia (TSSD), an assessment protocol designed to support teachers to screen for dyslexia. The current research evaluated the TSSD with a sample of 209 children in Years 4 to 6 (8–10 years-of-age) from New Zealand. The research investigated whether children could be accurately classified using tests from the TSSD, whether the three-step protocol described in the TSSD was a valid assessment approach, and what effect operationalising the term average at different cut-off points had on dyslexia screening. Children were classified using two cluster analyses. The first analysis was based on tests from the Woodcock Johnson IV and the second analysis was based on tests from the TSSD. Subsequent analyses investigated specific aspects of the TSSD protocol, including its sequential design and the placement of cut-off points. Results revealed a number of limitations to the TSSD approach. The authors discuss three changes that could be made to improve the validity and reliability of the TSSD, including a broader assessment of the decoding and language comprehension constructs; directing teachers to assess both decoding and language comprehension, irrespective of a child’s language comprehension ability; and placing a greater emphasis on discrepancy bands over cut-off points.