To determine the prevalence of parent-rated developmental concern using the ESSENCE-Q (Early Symptomatic Syndromes Eliciting Neurodevelopmental Clinical Examinations-Questionnaire, 12-items, score range 0-24) and to ascertain the predictive validity and optimal cutoff level of the instrument in a school-based sample of 11-year-old children.In a cross-sectional, school-based study, participants underwent a clinical assessment by a physician and a psychologist, teachers and parents completed the SDQ (Strength and Difficulties Questionnaire), medical health records and national tests were reviewed, and parents independently completed the ESSENCE-Q. In a case-conference outcomes were defined as a) the need for further clinical work-up due to suspected neurodevelopmental problems (NDPs) and b) degree of investigator-rated symptoms/impairment from NDPs on the CGI-S (Clinical Global Impression-Severity instrument, range 1-7, 4-7 defined as clinically symptomatic). Classification and optimal cutoffs of the ESSENCE-Q were determined using ROC (Receiver Operating Characteristic) analysis.Out of 343 eligible children, 223 enrolled, of whom 173 (50% of all eligible) had a parent-rated ESSENCE-Q. At least one of the 12 possible concerns was reported by parents of 36% of participants. Overall, in 101 (57%) participants a work-up was warranted, and 64 (37%) were clinically symptomatic from NDPs. The AUC of the ESSENCE-Q in detecting need for work-up was 0.70 (95% confidence interval [CI] 0.63-0.77), and the AUC in detecting clinically symptomatic participants was 0.82 (95% CI 0.76-0.88). ESSENCE-Q ratings correlated positively with CGI-S scores (r=0.48, p6 conferred few false positives cases with positive likelihood ratios >10 and positive predictive values of 86% or more.This study of the ESSENCE-Q in 11-year-old children suggests it might be an acceptable instrument for screening of NDPs in children in middle school, optimally in conjunction with other methods.