Return Value based on highest number, comparing rows

Anonymous , Try

new column = if([YearMonth] = maxx(filter(table, [ID] = earlier([ID])),[YearMonth]),1,0)

or

new measure = if(max(Table[YearMonth]) = maxx(filter(allselected(table), [ID] = max([ID])),[YearMonth]),1,0)

Hi, Anonymous 

Based on your description, I created data to reproduce your scenario. The pbix file is attached in the end.

Table:

You may create a custom column with following m codes.

let 
id=[ID],
maxyearmonth=List.Max(
    Table.SelectRows(#"Changed Type",each [ID]=id)[YearMonth]
)
in 
if [YearMonth]=maxyearmonth
then 1 else 0

Best Regards

Allan

If this post helps, then please consider Accept it as the solution to help the other members find it more quickly.