To the Editor In a recent issue of JAMA Internal Medicine, Kravitz and colleagues1 presented a randomized clinical trial comparing n-of-1 trials with usual care. Use of n-of-1 trials is highly relevant to recent emerging themes in health research, such as patient-centered research as well as personalized and precision medicine. Use of n-of-1 trials has been shown as useful across a broad range of health conditions and a diverse array of health interventions.2 The Oxford Centre for Evidence-Based Medicine considers n-of-1 trials level 1A evidence.3