Measuring High-Priority Outcomes in Autistic Adults: Initial psychometric assessment of the instruments in the AASPIRE Measurement Toolkit

Background: Adult autism services research is hampered by a lack of accessible self-reported outcome measures. The AASPIRE Outcomes Project used a community-based participatory research (CBPR) approach to create and test the AASPIRE Measurement Toolkit, a set of accessible survey instruments for use in real-world settings. The core toolkit contains 12 characteristics modules and 19 outcome measures, each with self-reported and caregiver-reported versions. Methods: In a prior phase of the project, we collaboratively adapted, revised, or co-created all instruments. We used our CBPR-nested Delphi process, our collaborative adaptation/creation process, and cognitive interviews to ensure accessibility and content validity. We then conducted a longitudinal survey to validate the 19 outcome measures in a pragmatic sample of 870 autistic adults from two healthcare systems, two disability service systems, and the larger autistic community in the United States. Participants completed surveys at 3 time points over 12-18 months. A 15% random subset completed an additional retest survey 2 weeks after the second time point. We assessed 1) accessibility using completion rates and perceived ease of use; 2) internal consistency using Cronbach's alphas and omegas; 3) convergent validity using Pearson's correlations; 4) two-week test-retest reliability using interclass correlation coefficients; and 5) six-month responsiveness to change by comparing self-perceived change with change in scores. Results: Over 90% of participants reported the survey items were easy to understand; over 90% of participants who started the survey completed all applicable sections at each time point; and participants answered 99% of items on each instrument. The outcome measures and their pre-determined subscales demonstrated strong accessibility, content validity, internal consistency reliability, test-retest reliability, convergent and discriminant validity, and responsiveness to change. Conclusion: The AASPIRE Measurement Toolkit is accessible and includes 19 outcome measures with strong initial psychometric properties. We will report in-depth assessments of construct and structural validity separately for each measure. All instruments are available for free and can help clinicians, service providers, advocacy organizations, and researchers assess the effectiveness of interventions and follow changes in outcomes over time.