BACKGROUND: Although evidence-based assessments are the cornerstone of evidence-based treatments, it remains unknown whether incorporating evidence-based assessments into clinical practice enhances therapists' judgment of therapeutic improvement. This study examined whether the inclusion of youth- and parent-reported anxiety rating scales improved therapists' judgment of treatment response and remission compared to the judgment of treatment-masked independent evaluators (IEs) after (a) weekly/biweekly acute treatment and (b) monthly follow-up care. METHODS: Four hundred thirty six youth received cognitive-behavioral therapy (CBT), medication, CBT with medication, or pill placebo through the Child/Adolescent Anxiety Multimodal Study. Participants and parents completed the following anxiety scales at pretreatment, posttreatment, and follow-up: Screen for Childhood Anxiety and Related Disorders (SCARED) and Multidimensional Anxiety Scale for Children (MASC). IEs rated anxiety on the Clinical Global Impression of Severity (CGI-S) and Improvement (CGI-I) at posttreatment and follow-up. Therapists rated anxiety severity and improvement using scales that paralleled IE measures. RESULTS: Fair-to-moderate agreement was found between therapists and IEs after acute treatment (kappa = 0.38-0.48), with only slight-to-fair agreement found after follow-up care (kappa = 0.07-0.33). Optimal algorithms for determining treatment response and remission included the combination of therapists' ratings and the parent-reported SCARED after acute (kappa = 0.52-0.54) and follow-up care (kappa = 0.43-0.48), with significant improvement in the precision of judgments after follow-up care (p < .02-.001). CONCLUSION: Therapists are good at detecting treatment response and remission, but the inclusion of the parent-report SCARED optimized agreement with IE rating-especially when contact was less frequent. Findings suggest that utilizing parent-report measures of anxiety in clinical practice improves the precision of therapists' judgment.