Based on the latest version, CMS169v3, the denominator is limiting the population to encounters from the first day of the MP (although the logic evaluates to beginning the second day of the MP) and the 323rd day of the MP. This would account for patients in the denominator who were diagnosed 42 days before the end of the MP and treated on the last day of the MP. The logic is stating that should there be an encounter in the first 323 days in the MP, exclude encounters that were not within 180 days of an active Diagnosis of Unipolar / bipolar depression, an active anti-depression or mood stabilizer medication, and encounters within 180 days during which an active diagnosis was made for unipolar/bipolar depression, and encounters that started within 180 days one of the following events: ◦ OR: "Procedure, Performed: BH Electroconvulsive Therapy" ◦ OR: "Procedure, Order: BH Electroconvulsive Therapy" ◦ OR: "Occurrence A of Medication, Order: BH Antidepressant Medication" ◦ OR: "Medication, Order: BH Mood Stabilizer Medication" ◦ OR: "Procedure, Performed: BH Counseling for Depression" ◦ OR: "Procedure, Order: BH Counseling for Depression" ◦ OR: "Encounter, Order: BH Outpatient Psychotherapy" ◦ OR: "Encounter, Performed: BH Outpatient Psychotherapy" The intent as stated in the header of the measure says:” The existence of a 'new diagnosis' is established by the absence of diagnoses and treatments of unipolar depression or bipolar disorder during the 180 days prior to the diagnosis” So, the logic will never consider encounters in the denominator that occur after Nov 19th of the year, even if it occurs within the MP.