Psychometric properties of the Beliefs About Adults with ID Scale in American physicians: Application of classical test and Rasch measurement theories.
The 12-item BAID scale reliably measures physician bias toward adults with ID and is ready for use in medical education.
01Research in Context
What this study did
McQuaid et al. (2024) tested a new 12-item survey called the BAID. BAID stands for Beliefs About Adults with ID Scale. The team gave the survey to American physicians. They used two ways to check if the survey worked: classical test theory and Rasch analysis.
What they found
The BAID scale passed every psych test. It measures one clear thing: wrong ideas doctors hold about adults with intellectual disability. It is reliable and valid. In short, the tool is ready for real-world use.
How this fits with other research
Scior et al. (2011) built the IDLS for the general public. McQuaid et al. (2024) narrowed the lens to doctors and trimmed the item count from many to twelve. Prigge et al. (2013) created the ATTID with five attitude factors. The new BAID keeps things simple by tracking only faulty beliefs, making scoring and teaching faster.
Dembo et al. (2023) and Vassos et al. (2023) also used Rasch methods for adult-ID tools. Their success gave A et al. confidence that Rasch would work for the BAID too. The pattern shows a field moving toward short, Rasch-tested scales.
Granieri et al. (2020) showed Rasch can work across wide age spans. A et al. focus on adults only, so the BAID is even shorter and more targeted. No clash appears; the studies simply refine the approach for each setting.
Why it matters
You now have a quick, doctor-facing bias ruler. Slip the 12 items into grand-rounds surveys or medical student pre-post tests. A low score flags hidden stigma you can tackle with role-play or contact-based training. The scale is free, short, and psychometrically sound, so you can start measuring change tomorrow.
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02At a glance
03Original abstract
BACKGROUND: Physicians' erroneous assumptions about individuals with intellectual disability (ID) negatively impact the quality of care provided to this population. This study aimed to investigate the psychometric properties of the Beliefs About Adults with ID (BAID), an instrument we developed for measuring physicians' erroneous assumptions about adults with ID. METHODS: Two hundred ninety-two American physicians participated. Classical test theory and Rasch measurement theory were used to refine the scale (through item analysis, exploratory factor analysis, infit and outfit mean-squares statistics, and differential item functioning) and investigate its psychometric properties (functioning of the response scale, reliability, and validity). RESULTS: The BAID provided a unidimensional, reliable, valid, and precise measure in assessing high levels of erroneous assumptions. It showed convergent and divergent validity with the different factors of a scale measuring attitudes towards ID. The BAID items were discriminant, non-redundant, unambiguous, and invariant across gender and previous ID training. The BAID response scale was found to be appropriate for measuring physicians' erroneous assumptions about adults with ID. CONCLUSIONS: BAID is a brief instrument with good psychometric properties to assess erroneous assumptions about adults with ID in physicians of different genders and who have/have not previously received ID training. Therefore, it might be helpful for research and medical education purposes.
Journal of intellectual disability research : JIDR, 2024 · doi:10.1111/jir.13143