Rank Measure

bdehning since you're not using the tiebreaker variable, you can get rid of it all

IF(
    ISINSCOPE( 'InjuryCause'[Cause Grouping]),
    RANKX (
        CALCULATETABLE (
            VALUES ( 'InjuryCause'[Cause Grouping]),
            ALLSELECTED ( 'InjuryCause'[Cause Grouping] )
        ),
        [Count of Total Gross Incurred] + [Sum of Total Gross Incurred],
        ,
        DESC,
        DENSE
    )
)

I would need a tie breaker though as original data from Count only is   

1

2

3

4

5

5

5

5

5 

I ran the above and it ran and gave results of ranking I was looking,  but is it only adding the Sum to the count and then ranking and we only got lucky?     I do need the [Sum of Total Gross Incurred] as tie breaker if Count results in ties.   

bdehning that's correct.

You need both the sum and the count. One of the two will act as your tiebreaker.

I appreciate your help.

But we actually want to find the top 5 by count first and then use the Sum of Total Gross as tie breaker.    If Top 5 is found 1-5, then no Sum is needed.  

If we get the Top Part working above and you understand how I need Sum to be used, we could be getting close