Variability is not flexibility: Emotion regulation switching predicts increased momentary distress when context is stable.

= 158, 12,217 observations), we applied the Bray-Curtis dissimilarity index-a computational tool that quantifies the type and degree of change between two profiles (i.e., patterns of ER and context)-to test whether ER effort scaling (i.e., endorsement changes) and strategy switching (i.e., replacement changes) predict momentary distress differently depending on whether context remains stable or changes. Greater moment-to-moment strategy switching predicted higher negative affect (Study 1) and momentary psychopathology symptoms (Study 2) when context was stable. These findings challenge the practice of using variability as a proxy for flexibility, underscoring that true flexibility cannot be evaluated without directly assessing context. We discuss implications for research on ER flexibility and psychopathology, emphasizing the need to prioritize rigorous context assessment in advancing clinical science. (PsycInfo Database Record (c) 2026 APA, all rights reserved).