Two different theoretical approaches were compared to determine the optimal cutoff scores for the Ages and Stages Questionnaires: Social-Emotional (ASQ: SE), a social-emotional screening test. Cutoff scores based on statistical decision theory modeling, Receiver Operator Characteristics (ROC), were compared with cutoff scores obtained using Item Response Theory (IRT) measurement theory modeling. The purposes of this comparison were (a) to offer alternative perspectives on the computation and function of cutoff scores, and (b) to obtain appropriate cutoff scores for the ASQ: SE screening test. Results are presented for both analyses, ROC and IRT. Collectively, results from the two approaches offer comparable solutions to persistent problems arising when screening decision rules are needed. Results underscore the psychometric integrity of the ASQ: SE cutoff scores.