Z-Scores the LoD Edition!

Version 3

    So I noticed that there wasn't an example workbook yet on how to calculate Z-Score using LoDs.


    In this example I copied the method used in


    Calculating Z-scores | Tableau Software


    So that comparisons can be made (Granted, I am using a different version of SuperStore).


    In the example above, Z-Score is calculated as follows


    ( SUM([Sales]) - WINDOW_AVG(SUM([Sales])) )




    The LoD Alternative is


    ({ FIXED [State] : SUM([Sales]) } - { FIXED : AVG({ FIXED [State]: SUM([Sales]) }) })


    { FIXED : STDEVP({FIXED [State] : SUM([Sales])}) }


    Both, calcs result in the same output.


    11-17-2015 8-15-03 AM.png


    The biggest benefit you get from using an LoD alternative is the ability to control the grain at which the Z-Score is calculated and to which level of detail you wish to return it. This gives us much more flexibility/control over outliers in our datasets.


    I used FIXED in my example for ease of use, but INCLUDE/EXCLUDE LoDs could be used as well. However INCLUDE/EXCLUDE LoDs must be aggregated, which could result in less flexibility with the data.


    Any suggestions on how to improve this workbook is highly appreciated.


    And, of course, if I have done anything incorrectly here, please let me know!