For month-to-date, use measure A, otherwise use measure B

[bubblepop]

There are two measures, A and B, that use different data sources. I want to use these measures in a larger measure, C. In C, I want the logic to be, for the current month (month to date), use measure A, otherwise, use measure B.

I know there is MONTH(NOW()) which returns the current month, but I don't know how to use a second variable that keeps track of the month to compare it to this month to date. 

So something of the sort for measure C:

IF (var == MONTH(NOW()):

[A]

ELSE

[B]

Need help figuring out what to set var to. Measure C will be displayed in a visual card as a numerical value and has a date history, slice-able by month.

[V-lianl-msft]

Based on your description, you need to create a calendar table as a bridge table. Use the date in the calendar table as a condition, and then create an IF statement. See if this works

[Ashish_Mathur]

Hi,

You should ideally build a Calendar Table and from there build 2 slicer visuals - Year and Month name.  Select a certain Year and Month name.  Write this measure

Measure C = if(and(selectedvalue(Calendar[Year])=2021,selectedvalue(Calendar[Month name])=format(today(),"mmmm")),[Measure A],[Measure B])

Hope this helps. 

[lbendlin]

"I want to use these measures in a larger measure"

That is considered bad practice.  Rather, write each measure individually.

Use Calculation Groups for what you are trying to achieve.