Difference when calculating Standard Deviation in Excel and DAX

  • Hi experts,

    Not sure why I am getting different results when calculating standard deviation in Excel and DAX using the same data sample.

    In Excel using STDEV.S(C9:N9) the result is 2176



    Mth_1

    Mth_2

    Mth_3

    Mth_4

    Mth_5

    Mth_6

    Mth_7

    Mth_8

    Mth_9

    Mth_10

    Mth_11

    Mth_12

    StDev




    12118

    8059

    9180

    6352

    6863

    6797

    8548

    7657

    8845

    7063

    6352

    2916

    2176

    Using DAX function STDEVX.S the result is 342

    STD (12mth):=STDEVX.S(RawData,CALCULATE([Mth1]+[Mth2]+[Mth3]+[Mth4]+[Mth5]+[Mth6]+[Mth7]+[Mth8]+[Mth9]+[Mth10]+[Mth11]+[Mth12])) = 342


    Gilly

  • It would be clearer with a sample workbook, but I think you are doing two completely different calculations. Your Excel one is the standard deviation of the totals for each month, whereas your DAX one looks like the standard deviation for the total of all months for each row of your table.

    Rory
    Theory is when you know something, but it doesn’t work. Practice is when something works, but you don’t know why. Programmers combine theory and practice: nothing works and they don’t know why