Addressing Common Problems in Autism Research: cohort development and sample description for a participatory, real-world, longitudinal study of outcomes in autistic adults.

Adult autism services research is plagued by methodological challenges, including difficulty obtaining representative or heterogeneous samples and a frequent mismatch between experimental methodologies and real-world settings. The AASPIRE Outcomes Project used a community-based participatory research (CBPR) approach to 1) create the AASPIRE Measurement Toolkit - a set of self- and caregiver-reported accessible outcome measures to evaluate health and social services, and 2) explore factors predicting changes in outcomes. We previously used a CBPR-nested Delphi process to identify high-priority outcomes and adapted or created instruments to measure them. We conducted a longitudinal survey to validate these measures in a pragmatic sample of autistic adults from two healthcare systems, two disability service systems, and the larger autistic community in the United States. This paper describes our study methods and the sample’s baseline characteristics. We collected baseline data from 870 participants. Follow-up response rates were >80% for the 2nd and 3rd timepoints. The sample includes strong heterogeneity. As expected, sample characteristics differed markedly between the 3 subcohorts. Lessons from our experience may help other researchers devise strategies to effectively recruit heterogeneous samples of autistic adults across various settings. This cohort may allow researchers to better understand what influences outcomes in autistic adults.