For CMS-65, it is possible for a patient to be in the denominator and be mathematically unable to meet the numerator. By QDM definitions, date granularity is a step function, so the element <= 6 months is equivalent to 7 months minus one day, which in the case of the Initial Population/Denominator, means that an initial encounter (Occurrence A) in the month of July should be counted. However, a patient with Occurrence A in July cannot meet the numerator requirement of a second encounter (Occurrence B) in the measurement period >= 6 months after Occurrence A, which means that such a patient could be included in the denominator but never be included in the numerator.