Barriers to child developmental screening lead to delayed diagnosis and intervention. babyTRACKS, a mobile application for tracking developmental milestones, presents parents their child's percentiles computed relative to crowd-based data. This study evaluated correspondence between crowd-based percentiles and traditional development measures. Research analyzed babyTRACKS diaries of 1951 children. Parents recorded attainment age for milestones across Gross Motor, Fine Motor, Language, Cognitive, and Social domains. Fifty-seven parents completed the Ages and Stages Questionnaire (ASQ-3), and 13 families participated in the Mullen Scales of Early Learning (MSEL) expert assessment. Crowd-based percentiles were compared with: Centers for Disease Control (CDC) norms for comparable milestones, ASQ-3 and MSEL scores. babyTRACKS percentiles correlated with the percentage of unmet CDC milestones, and with higher ASQ-3 and MSEL scores across several domains. Children who did not meet CDC age thresholds had lower babyTRACKS percentiles by about 20 points and those at ASQ-3 risk had lower babyTRACKS Fine Motor and Language scores. Repeated measures tests showed significantly higher MSEL versus babyTRACKS percentiles in the Language domain. Although ages and milestones in diary varied, the app percentiles corresponded with traditional measures, particularly in fine motor and language domains. Future research is needed for determining referral thresholds while minimizing false alarms.
Keywords: child development; crowdsourcing; mobile health; parenting; tracking.