Minimum clinically important difference and substantial clinical benefit: Does one size fit all diagnoses and patients?

There is increasing emphasis on the need to routinely utilize validated outcomes measures to assess the treatment effect of both operative and nonoperative management of spinal disorders. The minimum clinically important difference (MCID) describes at what point a marginal treatment effect is clinically relevant (threshold). Substantial clinical benefit (SCB) is a measurement that is intended to identify changes in outcomes that are clinically important. This review will discuss how MCID and SCB are calculated and relative criticisms of each measure; as each is determined based on patient-reported outcomes and does not incorporate cost analysis, the use of these measures has inherent limitations.