Introduction to the special section: More than measurement error: Discovering meaning behind informant discrepancies in clinical assessments of children and adolescents.

Discrepancies often arise among multiple informants' reports of child and adolescent psychopathology and related constructs (e.g., parenting, family relationship quality and functioning, parental monitoring). Recently, studies using various designs (laboratory, longitudinal, randomized controlled trial, meta-analysis) have revealed that discrepancies among informants' reports (a) yield important information regarding where children express behaviors (time course, features of the context[s] of behavioral expression) and about the informants who observe their expression, (b) demonstrate stability over time in both community and clinic settings, (c) predict poor child and adolescent outcomes in ways that the individual informants' reports do not, and (d) can be used to identify meaningful treatment outcomes patterns within randomized controlled trials. Using existing data sources, the articles in this special section expand upon this emerging body of research. In particular, the articles illustrate how clinical science and practice can use informant discrepancies to increase understanding of the causes and consequences of, as well as treatments for, child and adolescent psychopathology.