Getting PREVIOUSYEAR to respond to month filter

[Nankaina]

Apologies for the cramped tables, the forum won't let me edit them to be better sizes.

I have several columns of data unpivoted like so:

DATE	ATTRIBUTE	VALUE
Jan 2014	Column A	53
Jan 2014	Column B	8
Jan 2014	Column C	29
Feb 2014	Column A	56
Feb 2014	Column B	11
Feb 2014	Column C	20
...	...	...

So that I can have those columns presented in a Matrix like this:

	FY 2020	% Change	FY 2021	% Change	FY 2022	% Change
Column A	844	-5.5%	887	+5.1%	979	+10.4%
Column B	117	-1.7%	163	+39.3%	154	-5.5%
Column C	454	-5.4%	476	+4.8%	497	+4.4%

Where you can see that the "% Change" column is showing the change for each FY's Column sum compared to the previous year's.

For "% Change", I'm using this measure:

% Change = 
Calculate(
    Divide(
        (Sum('Unpivoted Table'[Value]) - Calculate(Sum('Unpivoted Table'[Value]), PREVIOUSYEAR('Fiscal Year Table'[Date], "September 30"))),
        Calculate(Sum('Unpivoted Table'[Value]), PREVIOUSYEAR('Fiscal Year Table'[Date], "September 30"))
    ),
    allselected('Fiscal Year Table'[Fiscal Month Number])
)

I'm not very good about indentation, hopefully that's legible. PREVIOUSYEAR is being used since our Fiscal Years end in September.

But here's the problem. When I put in a Slicer to only select a certain subset of Months in the Fiscal Year (for example, it's January, so let's make it four months), I get this:

	FY 2020	% Change	FY 2021	% Change	FY 2022	% Change
Column A	268	-70.0%	271	-67.9%	280	-68.4%
Column B	34	-71.4%	58	-50.4%	32	-80.4%
Column C	147	-69.4%	152	-66.5%	150	-68.5%

So even though the Values are changing just fine, the "% Change" column is now comparing those values to the ENTIRE previous year! My measure is already calculating on allselected('Fiscal Year Table'[Fiscal Month Number]), so I don't know why it's not calculating the PREVIOUSYEAR value for the selected month numbers.

(To clarify, 'Fiscal Year Table'[Fiscal Month Number] is a column which labels the months 1 through 12, starting in October and ending in September)

What do I need to do to the DAX to fix this, so it's applying the % Change only to months within the selection?

[Greg_Deckler · Accepted solution]

You may find this helpful - https://community.powerbi.com/t5/Community-Blog/To-bleep-With-Time-Intelligence/ba-p/1260000

Also, see if my Time Intelligence the Hard Way provides a different way of accomplishing what you are going for.

https://community.powerbi.com/t5/Quick-Measures-Gallery/Time-Intelligence-quot-The-Hard-Way-quot-TIT...

This specifically might help:

[Nankaina]

DATEADD! Of course! Pardon me going and making my life way harder than it had to be. Here I was thinking the PREVIOUSYEAR function was the only way to get this thing to do what it needed to.

The video you linked had exactly the Time Intelligence I was looking for. And not only is your solution shorter than mine, it's a general format so it can be reused! Thank you very much!