Last Year Sales Data is Off By One Week

Hi igibson,

According to my test, DATAADD and SAMEPERIODLASTYEAR both have a granularity of DAY. Maybe we have to get the same week by ourselves if you want the exact same week (same week number). 

CouldbeRight =
VAR currentWeeknum =
    MIN ( 'Date'[Weeknum] )
VAR currentYear =
    YEAR ( MIN ( 'Date'[Date] ) )
RETURN
    CALCULATE (
        FIRSTDATE ( 'Date'[Date] ),
        FILTER (
            ALL ( 'Date' ),
            'Date'[Weeknum] = currentWeeknum
                && YEAR ( 'Date'[Date] )
                    = currentYear - 1
        )
    )

As we can see from the picture, the first day of week 52 of 2010 is 12/19/2010, not 12/18/2010.

Best Regards!

Dale

A very simple soultion that I implemented was a change in the calendar. I simply used Fin_Week = WEEKNUM(DC03_Calendar[Date]+1,21).