How to calculate the average of values in a calculated column?

[Yiyi]

Hello all, 

I am new to DAX and I am totally stuck in calculating an dynamic average value for a calculated column. 

The calculated column for my table: 

Distinct Companies per Headline = CALCULATE(DISTINCTCOUNT('Main Data'[Company]), ALLEXCEPT('Main Data', 'Main Data'[HeadlineID]))

The table with the column: 

HeadlineID	Company	Distinct companies per headline
2113	A	2
2113	B	2
2114	C	1
2115	D	1

Now I would like to calculate the average of distinct companies per headline. 

The expected result would be:  Average = (2+1+1)/3  because HeadlineID 2113 is 2 times in the list. 

I tried to use summazie to create a new table so that only distinct headlineID and distinct companies per headline will be included. But it doesn't work. Can you help me in this? Thank you a lot! 

Average_Distinct_Companies_per_Headline = 
VAR SummaryTable =
    SUMMARIZE(
        'Data',
        'Data'[HeadlineID],  
        "Distinct_Companies_per_Headline",
        CALCULATE(DISTINCTCOUNT('Main Data'[Company]), ALLEXCEPT('Main Data', 'Main Data'[HeadlineID]))
    )
RETURN
    AVERAGEX(SummaryTable, [Distinct_Companies_per_Headline])

[johnt75]

Try

Average_Distinct_Companies_per_Headline =
AVERAGEX (
    VALUES ( 'Main Data'[HeadlineID] ),
    [Distinct Companies per Headline]
)

[Yiyi]

Thanks for your time!

For some reason I am not able to select [Distinct Companies per Headline] in the calculation. I wonder is it because this column is a calculated column. The DAX only allows to select measures here. 

[johnt75 · Accepted solution]

Ah, yes, I thought that was a measure. Try

Average_Distinct_Companies_per_Headline =
AVERAGEX (
    VALUES ( 'Main Data'[HeadlineID] ),
    CALCULATE (
        DISTINCTCOUNT ( 'Main Data'[Company] ),
        ALLEXCEPT ( 'Main Data', 'Main Data'[HeadlineID] )
    )
)

[Yiyi]

Looks good now, thanks a lot!