DAX to calculate sum for same period for defined year

[hp0655]

Does anyone know how to create a measure/variable that would calculate the sum for a defined year, while still keeping the month filters applied?

Phrased another way, I want to do "year-over-year" comparisons for each month in 2020 and 2021, but I want to compare them all to the same month in 2019 (i.e., pre-covid) rather than the previous year. So it would calculate the growth between, e.g., July 2020 vs July 2019, and between June 2021 vs. June 2019, etc.

[Anonymous · Accepted solution]

[Comparison to Base Year] =
// The Year column in your calendar
// must be an integer for this to
// work.
var CurrentYear = SELECTEDVALUE( YourCalendar[Year] )
// Change this setting if you want to make
// any other year the base one. You can even
// have a slicer with years (disconnected table)
// that will tell this measure which year to
// use as the base. You would harvest the value
// of the Base Year from the slicer and use here.
// For the time being it's hard-coded, of course.
var BaseYear = 2019
var Result =
	if( NOT ISBLANK( CurrentYear ),
		var YearsToGoBack = BaseYear - CurrentYear
		var CurrentValue = [YourMeasure]
		var BaseYearValue =
			CALCULATE(
				[YourMeasure],
				DATEADD(
					'YourCalendar'[Date],
					YearsToGoBack,
					YEAR
				)
			)
		var Growth_ = 
			DIVIDE(
				CurrentValue - BaseYearValue,
				BaseYearValue
			)
		return
			Growth_
	)
return
	Result

[hp0655]

this worked perfectly - thank you!!