Transitioning from Tableau - calculated Measure

[daniel_krantz_4]

I'm having alot of trouble with this one. In Tableau, I have a measure called "% Difference" - calculated as "ZN([%Pos Response]) - LOOKUP(ZN([%Pos Response]), -1)". This allows me, when I put Years in the columns area, to see the %Difference by year (there are thousands of rows, but only 3 years right now). The -1 telling it to compare with the previous year.

I cannot figure out how to transition this to PowerBi. 

%Pos Response is a calculated measure I've created in PowerBi that is calculated as follows (using two calculated columns): divide(sum([Count Positive]), sum(Data[PosNeg])).

Do people have ideas on how this can transition to PowerBI? There are a number of different values that I am needing this %Difference for, including some where I am hoping to drill down from "Question Group" to "Question"

[Anonymous · Accepted solution]

Hi @daniel_krantz_4 

Maybe you can try this:

Here I create a measure:

% Difference =
VAR _currentYear =
    YEAR ( MAX ( 'Table'[Date] ) )
VAR _previousYear =
    CALCULATE (
        MAX ( 'Table'[Date] ),
        FILTER ( ALLSELECTED ( 'TABLE' ), YEAR ( 'TABLE'[Date] ) < _currentYear )
    )
VAR CurrentYearValue =
    CALCULATE (
        [%Pos Response],
        FILTER ( ALLSELECTED ( 'Date' ), YEAR ( 'Table'[Date] ) = _currentYear )
    )
VAR PreviousYearValue =
    CALCULATE (
        [%Pos Response],
        FILTER ( ALLSELECTED ( 'Date' ), YEAR ( 'Table'[Date] ) = _previousYear )
    )
RETURN
    IF (
        NOT ISBLANK ( CurrentYearValue ),
        ( CurrentYearValue - PreviousYearValue ) / PreviousYearValue,
        BLANK ()
    )

 You can change the 'Table'[Date] into your own table's Date column.

Best Regards

Zhengdong Xu
If this post helps, then please consider Accept it as the solution to help the other members find it more quickly.

[daniel_krantz_4]

Thank you! I made some small changes to fit my data and realized I didn't need the divide statement, but this works! Here was the final code:

%Difference =
VAR _currentYear = MAX('Data'[Year])
VAR _previousYear =CALCULATE(MAX('Data'[Year]),
FILTER(ALLEXCEPT('Data', 'Data'[QGroup], 'Data'[Question]),'Data'[Year] < _currentYear))

VAR CurrentYearValue =CALCULATE([%Pos Response],
FILTER(ALLEXCEPT('Data', 'Data'[QGroup], 'Data'[Question]),'Data'[Year] = _currentYear))
VAR PreviousYearValue =CALCULATE([%Pos Response],
FILTER(ALLEXCEPT('Data', 'Data'[QGroup], 'Data'[Question]),'Data'[Year] = _previousYear))
RETURN
IF(NOT ISBLANK(CurrentYearValue),CurrentYearValue - PreviousYearValue, BLANK())