This study examined the agreement between the Ages & Stages Questionnaires, third edition (ASQ-3), and the Ages & Stages Questionnaires: Social-Emotional, second edition (ASQ:SE-2), and investigated the relationship of the overall indication of "parental concerns" about their child's behavior on the ASQ-3 and the results of the ASQ:SE-2. A large and U.S. representative sample of 16,739 birth to 6 years old children was used to calculate agreements (1) between the ASQ-3 and the ASQ:SE-2, as well as (2) between the indication of "parental concerns" about their child's behavior on the ASQ-3 and the results from the child's ASQ:SE-2. Findings indicated 0.80 agreement between "typical" classifications on the ASQ-3 and the ASQ:SE-2; as well as 0.57 agreement on the "at-risk" status. When parents indicated a "behavioral concern" about their child on the ASQ-3 overall questions, 74% of these children were identified by a subsequent ASQ:SE-2. High agreement on the "at-risk" status between developmental and social-emotional screening tests was found. High agreement between parental concerns about child's behavior and results of the social-emotional screening test was found. This finding adds to the foundations of research on the importance of parental input in the early identification processes and can inform efforts to increase the efficiency of the screening process.