Rasch analysis of the assessment of children's hand skills in children with and without disabilities.
The ACHS is a Rasch-approved, single-ruler scale that cleanly measures everyday hand skill across disabled and typical children.
01Research in Context
What this study did
Chien et al. (2011) ran a Rasch check on the Assessment of Children's Hand Skills (ACHS).
They watched kids with and without disabilities do everyday hand tasks.
The goal was to see if the scale truly measures one thing: real-life hand skill.
What they found
The ACHS passed the Rasch test.
It lined up as a single, solid ruler from low to high hand skill.
Kids with disabilities scored lower, typical kids scored higher, and no items misfit.
How this fits with other research
Wuang et al. (2009) did the same Rasch tidy-up on the BOT-2 motor test.
They also cut misfit items and made a shorter, cleaner scale for kids with ID.
Koudys et al. (2025) asked if adding motion-capture cameras changes AHA scores.
They found no change, so tech add-ons can be used without hurting validity.
Together, the three papers show Rasch is the go-to method for sharpening pediatric motor tests.
Why it matters
You now have a brief, observation-based scale that truly ranks hand skill.
Use the ACHS to set clear baselines and show parents real progress in daily tasks like buttoning or using a spoon.
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02At a glance
03Original abstract
The Assessment of Children's Hand Skills (ACHS) is a new assessment tool that utilizes a naturalistic observational method to capture children's real-life hand skill performance when engaging in various types of activities. The ACHS also intends to be used with both typically developing children and those presenting with disabilities. The purpose of this study was to further investigate the construct validity of the ACHS using the Rasch analysis. Participants included 64 typically developing children and 70 children with disabilities in the age range of 2-12 years. Rasch analysis results confirmed the appropriateness of the ACHS's 6-level rating scale in this combined group of children. All 22 activity items and 19 of the 20 hand skill items in the ACHS formed a unidimensional scale and were ordered according to difficulty as clinically and developmentally expected. The ACHS also exhibited sufficient response validity and item-difficulty range when applied to children with disabilities as well as typically developing, preschool-age children. Furthermore, less than half of the ACHS items were found to exhibit differential item functioning with regard to gender (5 activity items) and disability (2 activity items and 7 hand skill items). Therefore, the ACHS shows preliminary evidence of construct validity for its clinical use in assessing children's hand skill performance in real-life contexts.
Research in developmental disabilities, 2011 · doi:10.1016/j.ridd.2010.09.022