an argument of function power has the wrong data type or the solution is too ...

BTW, using variables and a SWITCH makes this kind of measure much easier to read.

Try something like this:

Output =
VAR _X = SELECTEDVALUE ( 'Horizon'[X] )
VAR _Qtr  = SUM ( '3m'[Y] ) / SUM ( Value[Y] )
VAR _Year = SUM ( '12'[Y] ) / SUM ( Value[Y] )
RETURN
    SWITCH (
        _X,
        "3m (annualized)",
            IF ( _Qtr ^ 4 = 0, 0, ( _Qtr ^ 4 - 1 ) * 100 ),
        "3m",
            IF ( _Qtr = 0, 0, ( _Qtr - 1 ) * 100 ),
        "12m",
            IF ( _Year = 0, 0, ( _Year - 1 ) * 100 )
    )

Hi Anonymous 

Does AlexisOlson 's method help you resolve the issue? If does, please kindly Accept it as the solution. More people will benefit from it.

Or if you are still confused about it, please provide me with more details about your table and your problem or share me with your pbix file after removing sensitive data.

Refer to:

How to Get Your Question Answered Quickly - Microsoft Power BI Community

How to provide sample data in the Power BI Forum - Microsoft Power BI Community

Best Regards,
Eyelyn Qin