Need Help!! How to calculate different row items

Hi Perezjav 

I build a table like yours to have a test.

Firstly, you need to transform your table by unpivot column like pranit828  replied before. (Select three wave columns)

Result:

Then build a Slicer Table.

Slicer = VALUES('Table'[Wave])

Add an Index column in Table.

Index = RANKX(FILTER('Table','Table'[Category]=EARLIER('Table'[Category])),'Table'[Wave],,ASC)

Build a measure and build a matrix visual to achieve your goal.

vs Prior Wave = 
VAR _select =
    SELECTEDVALUE ( Slicer[Wave] )
VAR _selindex =
    CALCULATE (
        SUM ( 'Table'[Index] ),
        FILTER (
            'Table',
            'Table'[Category] = MAX ( 'Table'[Category] )
                && 'Table'[Wave] = _select
        )
    )
VAR _current =
    CALCULATE (
        SUM ( 'Table'[Value] ),
        FILTER (
            ALL ( 'Table' ),
            'Table'[Category] = MAX ( 'Table'[Category] )
                && 'Table'[Index] = _selindex
        )
    )
VAR _prior =
    CALCULATE (
        SUM ( 'Table'[Value] ),
        FILTER (
            ALL ( 'Table' ),
            'Table'[Category] = MAX ( 'Table'[Category] )
                && 'Table'[Index] = _selindex - 1
        )
    )
RETURN
    _current - _prior

Result is as below.

Default:

Select Wave2/Wave3 in Slicer:

You can download the pbix file from this link: Need Help!! How to calculate different row items

Best Regards,

Rico Zhou

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