The Integrated Self-Discrepancy Index: a reliable and valid measure of self-discrepancies.

In this article, we present the Integrated Self-Discrepancy Index (ISDI), a new method for measuring self-discrepancies (Higgins, 1987) that integrates idiographic and nomothetic methods to address important theoretical and methodological concerns in existing measures. In Study 1, 284 undergraduate participants completed the ISDI to measure ideal-own and ought-own self-discrepancies along with measures of dejection, agitation, cheerfulness, and quiescence. In Study 2, we used the ISDI to measure ideal and ought self-discrepancies from both own and other standpoints; 169 undergraduate participants completed measures of depressive symptoms and social anxiety approximately 1 week later. Data from both studies fully support the fundamental predictions of self-discrepancy theory: Ought self-discrepancies were uniquely related to agitation but not dejection, whereas ideal self-discrepancies were uniquely related to dejection but not agitation. In addition, comparisons to previously published data demonstrate that correlations between the ideal and ought self-discrepancies are significantly lower using the ISDI than using other measures of self-discrepancies, suggesting that the ISDI is better able to measure ideal and ought selves as distinct constructs. This measure may provide researchers with a simpler and more valid method to measure self-discrepancies, contributing to our understanding of the importance of self-discrepancies in many applied literatures.