With input from a stakeholder committee, the National Quality Forum identified recommendations for the practical application of the Diagnostic Process and Outcomes domain of the 2017 Measurement Framework  for measuring and improving diagnostic error and patient safety. The committee developed four ‘use cases’ (missed subtle clinical findings; communication failures; information overload; and dismissed patients) reflecting high priority examples of diagnostic error that can result in patient harm. The report includes comprehensive, broad-scope, actionable, and specific recommendations for implementing quality improvement activities to engage patients, educate clinicians, leverage technology, and support a culture of safety with the goal of reducing diagnostic errors.