Given the limitations of the evidence base, the writing committee felt strongly that no specific threshold should be required for these measures, though it did see value in collecting these data for institutional and operator quality assurance. The writing com- mittee also recognized the potential challenges of operators who are recently out of training or who transiently cease performing procedures because of job changes or health reasons (eg, preg- nancy). A potential unintended consequence of this measure that was discussed by the writing committee is that an operator might perform unnecessary procedures to achieve a threshold level. Future iterations of this measure will need to also address whether adjunctive coronary procedures (eg, fractional flow reserve, intravascular ultrasound) and noncoronary procedures (eg, transcatheter aortic valve replacement) should be included in these assessments of operator and institutional volume, given that these techniques require overlapping technical skills. 6. Potential Measures Considered But Not Included in This Set 6.1. Process Measures The writing committee considered several additional process measures for inclusion. A longitudinal measure assessing use of dual-antiplatelet therapy at 30 days and 1 year was considered. Although such a measure has a greater likelihood of improving care, the logistical challenges of collecting longitudinal drug data on an outpatient basis made it difficult to implement this measure at the present time. We are hopeful that advances in information technology, electronic health records, and outpatient registries will make reliably collecting these data possible in the future. We also examined additional measures related to ad hoc PCI (PCI performed during the same session as diagnostic angio- gram) and multivessel PCI. These measures focused on exam- ining the core question of whether the PCI was appropriate in the context of additional therapeutic options, like medical therapy and coronary artery bypass surgery. 