Discrepancies among informants' ratings of child psychopathology have important implications for diagnosis, assessment, and treatment. Typically, parents and children complete measures (e.g., self-report checklists, diagnostic instruments) to assess child dysfunction. Ratings gathered from these sources reveal relatively little agreement on the nature and extent of the child's social, emotional, and behavioral problems. This article reviews and illustrates the most frequently used methods of measuring informant discrepancies in the clinical child literature (i.e., raw difference, standardized difference, and residual difference scores) and outlines key considerations to influence their selection. The authors conclude that frequently used methods of measuring informant discrepancies are not interchangeable and recommend that future investigations examining informant discrepancies in clinical child research use the standardized difference score as their measure of informant discrepancies. (PsycINFO Database Record (c) 2007 APA, all rights reserved)(from the journal abstract)