The Thorny Nature of Predictive Validity Studies on Screening Tests for Developmental-Behavioral Problems

Over the last few years, several researchers have focused on the predictive validity of developmental-behavioral screening tools. 1–11 Predictive validity studies compare the results of a screening test administered at a single point in time (referred to hereafter as time 1) to the results of a diagnostic test or battery administered 3 months to several years later (time 2). 12 Unlike concurrent validity studies in which both screening and diagnostic measures are administered at the same time to determine the sensitivity and specificity of a screen, predictive validity studies depend on longitudinal measurement and focus on how well a screen predicts future developmental status. As a consequence, predictive validity research offers a critical illustration of whether a screening test measures dimensions of development that are enduring and have a meaningful impact on children's long-term outcomes. As already stated by the American Academy of Pediatrics, a concerning, high-quality screening result should generate a referral to early intervention or special education, which has been shown to improve a child's developmental, behavioral, and/or school-readiness trajectory. 9, 13–17 Nevertheless, predictive validity studies on screening tests are also fraught with challenges, particularly because young children change rapidly. For example, at 18 months some children may not be talking much. By 24 months we expect much more. Some children who seemed fine at 18 months have begun to have trouble (eg, combining words). Others will have had the benefit of intervention and overcome earlier deficits. The adverse impact of psychosocial risk becomes more apparent with age. Developmental functions can be emergent, latent (not yet measurable), delayed, deficient, or disordered. 13 Measuring the moving target that is child development is not impossible, but it is one of the reasons that professional organizations such as the American Academy … Address correspondence to Frances Page Glascoe, PhD, 25 Bragg Dr, East Berlin, PA 17316. E-mail: frances. p. glascoeatvanderbilt. edu