Normalize values based on the first one

Hi zivhimmel

I would do something like this:

(I'm calling your fact table Data and assuming you have a related calendar table called Calendar with the relationship on the Date column, and a base measure called [Value] )

1. Define a measure [Value First Date]
   

   Value First Date =
   /* Optional check: Only return Value First Date up to the max date that actually appears in the fact table */
   IF (
       MIN ( 'Calendar'[Date] ) <= CALCULATE ( MAX ( Data[Date] ), ALL ( Data ) ),
       CALCULATE (
           [Value],
           CALCULATETABLE ( FIRSTDATE ( 'Calendar'[Date] ), ALLSELECTED ( 'Calendar' ) )
       )
   )

2. Define a [Value Normalized] measure:
   

   Value Normalized =
   DIVIDE ( [Value], [Value First Date] ) * 100