Is a Positive Developmental-Behavioral Screening Score Sufficient to Justify Referral? A Review of Evidence and Theory

Abstract

In their recommendations on screening for autism and developmental disabilities, the American Academy of Pediatrics recommends referral subsequent to a positive screening result. In this article, we argue that positive screening results are not always sufficient to justify a referral. We show that although positive predictive values are often low, they actually overstate the probability of having a disorder for many children who screen positive. Moreover, recommended screening thresholds are seldom set to ensure that the benefits of referral will equal or exceed the costs and risk of harm, which is a necessary condition for an optimal threshold in decision analysis. Drawing on recent recommendations for the Institute of Medicine/National Academy of Medicine, we discuss the implications of this argument for pediatric policy, education, and practice. In particular, we recommend that screening policies be revised to ensure that the costs and benefits of actions recommended in the event of a positive screen are appropriate to the screening threshold. We recommend greater focus on clinical decision-making in the education of physicians, including shared decision-making with patients and their families. Finally, we recommend broadening the scope of screening research to encompass not only the accuracy of specific screening instruments, but also their ability to improve decision-making in the context of systems of care.

Keywords: autistic disorder; decision-making; developmental disabilities; mass screening; sensitivity and specificity.

Figure 1

Visualization of sensitivity, positive predictive value (PPV), and threshold probability. (A) Normal distributions of screening scores. (B) Sensitivity and PPV: calculated from all true positive (TP), false positive (FP), or false negative (FN) results. (C) Threshold probability: calculated on the basis of frequency (f) of children from healthy and affected populations who score at the threshold.

Figure 2

Positive predictive value (PPV) and proportion who screen positive as a function of sensitivity, specificity, and prevalence.