Calculated Column for New Employee

Hi everyone,

I would like to create a reporting that shows new employees per month. For that I would like to have a calculated column that works out the 'New Employee' value and returns as '1' if the same employee number doesn not exist in the prior period.

Example: 1525 and 1526 return as '1' for 01/12/2019 as these employee code did not exist for 01/11/2019.

My challenge is,  mydataset has seperate calender table and employee data table and following DAX did not work.

I believe i need to create a connection.

New Employee =
VAR temp =
    FILTER (
        Table1,
        Table1[Employee Number] = EARLIER ( Table1[Employee Number] )
            && Table1[Period] < EARLIER ( Table1[Period] )
    )
RETURN
    IF ( COUNTROWS ( temp ) > 0, 0, 1 )

Your help really appreaciated and you can see the example pbix file here.

Thanks!