For such a small amount of DAX code, the Cohort measure hides perhaps one of the trickiest DAX computations ever devised, a computation that would likely give even DAX masters a moment's pause to understand how the calculation works. This calculation is only possible because of the peculiar interaction between particular, individual features of three DAX functions: GENERATE, DISTINCT, and CALCULATETABLE. Exactly how this calculation operates and why it does will be explained shortly, but first, let's go over the overall measure calculation.
The first table variable we created, __Table, contains a list of patients and diagnosis codes for patients that do NOT have all of the diagnoses selected in the slicer. This table contains ...
