Calculate the Average of a measure over selected months

[Lindino08]

Hello Power Bi Community! Hoping someone can help me out.

I have a measure which calulates the "Incident Rate" (IR). Formula for IR is:

IR = 'Injury Data'[Recordable Injuries] * 200000 / 'Injury Data'[Total Working Hours]

We have the IR placed on a monthly bar graph which is correct. Now we would like to add a Line y-axis to show a cumulative average of the IR based on the selected Months.

Red line is what I have drawn and need to create a formula for.

[Barthel]

Hey,

Assuming you have a calendar table called 'Calendar', this is the code you can use for a measure:

Cumulative Average =
VAR CurrentDate =
    MAX ( Calendar[Date] )
RETURN
    CALCULATE (
        'Injury Data'[Recordable Injuries] * 200000 / 'Injury Data'[Total Working Hours],
        ALLSELECTED ( Calendar ),
        Calendar[Date] <= CurrentDate
    )

Instead of redefining the IR measure in the above code, you can also refer to your already existing IR measure.

[Lindino08]

Thanks Barthel!

I tried your code and have different results (which is good) but not what we are looking for. Here is a screentshot. 

[Barthel]

Hey,

Just thinking out loud here. What kind of column is the 'Month' column? A string or value? The VAR CurrentDate must take the MAX of a value column, so that the less than or equal to statement works logically. Is that the case? If not, take the MAX of the column on which you base the sort order of 'Month', rather than 'Month' itself.

[Lindino08]

Good thoughts! I tried to change it to a calendar value column that I am pulling the month name from. Here is what I get. The second screen shot is of the relationship between the two tables I have and you can see the date columns. 

[Barthel · Accepted solution]

Hey,

I think it's because the ALLSELECTED function doesn't work properly this way. Could you try this code?

Cumulative Average =
VAR MinDate =
    CALCULATE ( MIN ( 'Employee Hours'[Date (Start of Month]) ), ALLSELECTED ( 'Employee Hours' ) )
VAR MaxDate =
    MAX ( 'Employee Hours'[Date (Start of Month])] )
RETURN
    CALCULATE (
        'Injury Data'[Recordable Injuries] * 200000 / 'Injury Data'[Total Working Hours],
        'Employee Hours'[Date (Start of Month])] >= MinDate,
        'Employee Hours'[Date (Start of Month])] <= MaxDate
    )

[Lindino08]

Prefect! You're Awesome! Thanks for the help.