Cumulative Rolling Average with multiple values on same date

Hi zenton ,

Based on your description I created simple data:

You can try creating an index column:

Try the following DAX:

Mean = 
VAR _historyindex=MINX(ALL('Labware'),'Labware'[Index])
VAR _firstindex=MAX('Labware'[Index])
RETURN
CALCULATE(AVERAGE('Labware'[Value]),FILTER(ALL('Labware'),'Labware'[Index]>=_historyindex&&'Labware'[Index]<=_firstindex))

Result:

Best Regards,
Zhu

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