We believe this measure will encourage more cardiac catheterization laboratories to participate in large multicenter databases and collaboratives to improve the evidence base to support quality efforts in PCI. 5.10. Annual Operator and Hospital PCI Volume The writing committee designated the operator procedure volume as appropriate for internal quality improvement only, as indicated in Appendix C. It is well recognized that operator volume, though useful, is a limited surrogate for quality. This is due partly to the dif culty of collecting volume data for individual operators, who can practice across numerous facilities and even states. The volume of the catheterization laboratory in which an operator works seems to be a more trustworthy surrogate for quality than does individual operator volume. Although updated rec- ommendations exist for operator and institutional volumes (24), they are still based on observational studies that looked at a variety of facility volume thresholds. However, the preponderance of evidence suggests that facilities that perform <200 PCIs per year have worse outcomes than facilities that perform more procedures. Given the limita- tions of the evidence base, the writing committee felt strongly that no speci c threshold should be required for these measures, though it did see value in collecting these data for institutional and operator quality assurance. The writing committee 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 (e.g., pregnancy). 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 (e.g., fractional ow reserve, intravascular ultrasound) and noncoronary pro- cedures (e.g.