 The study showed the value of taking into account other information besides the test result because the screener increased the predictive value from 44% to 56% by using her judgment not to refer some children with minor delays.In a study of two-stage screening, children were prescreened with Frankenburg’s Revised Prescreening Developmental Questionnaire and 421 with suspect scores were given the Denver II and evaluated by independent examiners.In children under 18 months the prevalence of abnormality was 0.19 on diagnostic tests, and the Denver II had a positive predictive value of 0.36, a negative predictive value of 0.90, a sensitivity of 0.67, and a specificity of 0.72.