Rumination is typically defined as the perseverative focus of attention on negative internal thoughts and feelings, which can increase the risk of developing—and severity once developed—of depression. It is thought the perseveration is caused by a deficit in inhibitory control in ruminators. Congruent with this hypothesis, estimates of inhibition in task switching—the n–2 task repetition cost—are negatively associated with estimates of rumination. However, estimates of individual differences of n–2 task repetition costs are hampered by (a) measurement error caused by trial-wise variation in performance, and (b) recent evidence suggesting much of the n–2 task repetition cost measures interference in episodic memory, not inhibition. The aim of the current study is to revisit the question of the association between the n–2 task repetition cost and measures of rumination by (a) statistically accounting for measurement error by estimating n–2 task repetition costs via trial-level Bayesian multilevel modelling, and (b) controlling for episodic interference effects on estimates of n–2 task repetition cost by utilising a paradigm capable of doing so. Together, these methodological and statistical improvements will provide a clearer estimate of the association between inhibition and rumination.