Development and validation of the Intellectual Disability Literacy Scale for assessment of knowledge, beliefs and attitudes to intellectual disability.
The IDLS is a quick, culture-fair way to measure and track public knowledge and stigma about intellectual disability.
01Research in Context
What this study did
The team built a new quiz called the Intellectual Disability Literacy Scale. They wanted one short tool that measures what the public knows and believes about people with ID.
Over the adults from five ethnic groups filled out the draft items twice, two weeks apart. The researchers then ran factor and reliability checks to see which questions hung together.
What they found
Twenty-eight items stayed in the final IDLS. Four clear factors emerged: knowledge, negative stereotypes, positive attitudes, and desired social distance.
The scale scored high on test-retest (0.81) and internal consistency (0.86). It worked equally well for Māori, Pacific, Asian, and European New Zealanders.
How this fits with other research
Van der Molen et al. (2010) had already built the 16-item Attitudes to Disability Scale. Their tool asks about general disability; the IDLS drills into ID-specific beliefs and adds a knowledge factor.
Cheves et al. (2026) moved the field forward with the OWLS-ID, a self-report distress scale for adults who have ID themselves. Scior et al. (2011) complements that work by measuring what the community thinks about those same adults.
de Bildt et al. (2005) and Green et al. (2020) show the Vineland family keeps tight psychometric standards for adaptive behavior. The IDLS meets a similar standard, but for public literacy instead of client skills.
Why it matters
You now have a free, 5-minute scale that spots gaps and bias in staff or community attitudes. Run it at your school, clinic, or parent workshop before and after inclusion training. Target the factors that score lowest—often stereotypes and social distance—to make your education effort data-driven and ID-specific.
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02At a glance
03Original abstract
Research into the general public's responses to individuals with intellectual disabilities has been dominated by attitudinal research. While this approach has unquestionably generated useful findings, it ignores important aspects, such as lay knowledge, explanatory models and beliefs about suitable interventions that can produce a multi-faceted understanding of public responses. This paper describes the development of a measure designed to assess respondents' intellectual disability literacy. Following a pilot with 114 participants, the IDLS was revised and then completed by 1376 members of the public (aged 18-78 years) from diverse cultural backgrounds. The measure was able to distinguish respondents who showed good intellectual disability literacy. Confirmatory factor analyses revealed four causal beliefs factors (adversity, biomedical, fate, environment) that accounted for 55% of the variance and three intervention beliefs factors (lifestyle, expert help, religion/spiritual,) that explained 52% of the variance. Test-retest reliability for these factors was good for all ethnic groups. The four-item social distance scale had good internal consistency for all ethnic groups and acceptable concurrent validity. The IDLS is a useful new tool to evaluate knowledge, beliefs and social distance to intellectual disability in lay people, is suitable for cross-cultural research and allows comparison of intellectual disability and mental health literacy in any given population.
Research in developmental disabilities, 2011 · doi:10.1016/j.ridd.2011.01.044