Selection and Development of Performance Measures The process for the selection and development of these ICH performance measures used an approach from the AHA/ASA Stroke Performance Oversight Committee similar to that used for the 2014 AHA/ASA ischemic stroke performance mea- Only Class I (high consensus for benefit) and Class III (high consensus for harm) recommendations according to the AHA/ASA criteria for recommendations and classification of Levels of Evidence were considered candidates for develop- ment into performance measures (Supplemental Tables 2 and correspondence to review all Class I and III recommendations from the 2015 AHA/ASA ICH guidelines for suitability to develop into performance measures. Potentially applicable metrics from the AHA/ASA Metrics for Measuring Quality of Care in Comprehensive Stroke Centers manuscript were also added to the list for consideration.19 Standard criteria for performance measure development were determined before initial review and were derived from principles set forth previ- ously by theAHA and theAmerican College of Cardiology.11,12 These criteria included (1) likelihood that measure adherence would result in improved patient outcomes; (2) interpretabil- ity; (3) actionability; (4) precise numerator and denominator that could be defined; (5) reliability; (6) validity; and (7) fea- sibility for implementation. On the basis of the writing group discussion and voting, if a specific guideline recommendation was felt not to meet the above criteria, then it was not moved forward for development as a potential performance measure. From this list of potential performance measures, sub- groups of the writing group developed formal measurement set specifications in draft form for each potential performance measure. These specifications included numerator, denomi- nator, period of assessment, data sources, rationale and spe- cific recommendations from which it was derived, method of reporting, and challenges to implementation. Each writing group member participated in the development of at least 2 draft performance measures. 