The goal of this consortium is to establish tools that can be used as biomarkers and/or sensitive and reliableobjective assays of social impairment in autism spectrum disorder (ASD) clinical trials. Specifically, we aim toaccelerate the development of effective treatments for social impairment in ASD by validating (a) outcomemeasures that will be sensitive and reliable assessments of response to treatment and (b)electroencephalography (EEG) and eye-tracking (ET) biomarkers that can be used to reduce heterogeneity ofsamples via stratification, indicate early efficacy, and/or demonstrate target engagement. The consortiumincludes five Collaborating Implementation Sites (“Sites”) to conduct a naturalistic, longitudinal study of preschool(3-5 years) and school-aged (6-11 years) children with ASD and typical development (TD) with IQ ranging from50-115. Children will be assessed across three time points (T1: Baseline, T2: 6 weeks, T3: 24 weeks) usingclinician, caregiver, and lab-based (LB) measures of social impairment, along with a battery of conceptuallyrelated EEG and ET tasks and independent ratings of clinical status. The Data Acquisition and Analysis Core(DAAC) will oversee consistent application of scientific standards and methodological rigor for data collection,processing, and analytics. We propose well-justified acquisition standards, many developed by field leaders inthis Core, and innovative analytics within an infrastructure designed to facilitate multi-site research. StandardOperating Procedures (SOPs) and Manuals of Procedures (MOPs) will ensure clear, replicable acquisitionprotocols and post-processing analytic approaches to assess EEG and ET as sensitive indicators of clinicalstatus, as stratification biomarkers for ASD, as sensitive and reliable indicators of change, and in relation to LB-based measures of social-communicative behavior and caregiver/clinician assessments. The DAAC will worktogether with the Sites and the Data Coordinating Core (DCC) under the oversight of the Admin Core and incoordination with federal and private partners in this collaborative agreement to: 1) design and implementexperimental protocols to ensure standardized data acquisition; 2) design and implement rigorous, scientificallyvalid, and replicable data processing of and artifact removal from data sets; 3) design and implement statisticalanalyses for biomarker evaluation, including: (a) selecting, implementing, and deriving EEG and ET biomarkersand LB measurement variables with good performance metrics (construct validity, test-retest reliability, stability,and discriminant validity); (b) examining the relationship and sensitivity among EEG and ET biomarkers, LBmeasures, clinician/caregiver assessments, and independent measures of clinical status; (c) evaluatinglongitudinal change in ET, EEG, and LB measures to identify if these measures will be sensitive measures forintervention trials.