Change this sentence: Also may be grouped for inclusion in a specific performance measure based on specific criteria (e.g., patient's age, diagnosis, prior MI). To: For measures that include multiple populations, different populations may have different denominators, grouping the denominators along specific criteria (e.g. patient's age, diagnosis, surgical procedures, prior MI). And have that be a separate paragraph from the following that discusses measure set. Add a link to the measure set definition in the measure set discussion.