Invariance of the Derailment Scale-6: Testing the measurement and correlates of derailment across adulthood.

Derailment, a newly mapped construct describing difficulty reconciling perceived changes in identity and self-direction, offers researchers a unique lens for understanding adjustment. As identity development is a lifelong process, establishing the impartiality of the primary measure for derailment across a broad age range is necessary. Across a cross-sectional sample of emerging, young, and midlife adults (N = 1,420), we tested preregistered hypotheses concerning whether the Derailment Scale-6 (DS-6) demonstrates measurement invariance, and the extent to which levels and correlates of derailment differ with age. The DS-6 exhibited configural, metric, and partial scalar invariance across the three age groups. In terms of effect size, statistical differences detected at the scalar level were hardly larger than negligible noninvariance effects, suggesting in sum that the DS-6 is adequate for assessing and comparing derailment among those roughly 18-70 years. In general, derailment was related to greater distress and identity exploration, and lower identity commitment, sense of purpose in life, and future time perspective (FTP). We further found that derailment shares a modest negative association with age; it is more positively associated with identity exploration among younger individuals; and it is more negatively associated with identity commitment, sense of purpose in life, and FTP among older individuals. With the broadest age range and most highly powered set of tests studying derailment to date, this investigation bolsters confidence in our tools for assessing derailment and has taken the initial steps toward sketching the form and function of perceived identity change over the lifespan. (PsycInfo Database Record (c) 2022 APA, all rights reserved).