In this article, we compare the nature and function of self-parent informant discrepancies for adolescent personality pathology using two methods: standard difference scores (SDS) and polynomial regressions. In total, 489 11- to 18-year-old youth (54% female) and their parents reported on youth personality pathology traits and general psychopathology. Findings supported convergence and divergence in parent- and self-reports. Potential utility of informant discrepancies also emerged, such that discrepancies on trait disagreeableness and trait compulsivity predicted youth externalizing problems using the SDS approach and the polynomial regression approach; however, the polynomial regression approach yielded a more complex and nuanced characterization of informant discrepancies than did the SDS approach. Taken together, these results suggest that polynomial regressions may provide a more comprehensive picture regarding the meaning and utility of informant discrepancies.