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. Author manuscript; available in PMC: 2018 May 22.
Published in final edited form as: Am J Epidemiol. 2018 Mar 1;187(3):592–603. doi: 10.1093/aje/kwx262

Figure 1.

Figure 1

Standard flow of study components for the Study to Explore Early Development, United States, 2007–2011. Potential cases of autism spectrum disorder (ASD) and developmental delay (DD) controls (non-ASD developmental disabilities) were identified from educational or clinical service providers. Population controls (POP) were identified from birth records. Incentive (Inc.) was given as check or gift card (varied by site operations), except with the Introductory Packet. The Introductory Packet incentive was a beach ball worth approximately $1. To be assigned to the potential-ASD protocol group, children had a previous ASD diagnosis and/or a Social Communication Questionnaire score of ≥11. To be assigned to the DD or POP control groups, children had a Social Communication Questionnaire score of <11 and remained associated with the source group from which they were identified. Final classification as a case of ASD or as a DD or POP control was based on the outcome of the developmental evaluation.