You can try this:
Rank SQKey 2 =
IF (
ISINSCOPE ( 'Dim Question'[Question Type] )
&& ISINSCOPE ( 'Dim Question'[Question] )
&& ISINSCOPE ( 'Fact Survey Answer'[Answer] ),
RANKX (
CALCULATETABLE (
SUMMARIZE (
'Fact Survey Answer',
'Dim Question'[Question],
'Dim Question'[Question Type],
'Fact Survey Answer'[Answer]
),
ALLSELECTED ( 'Fact Survey Answer' )
),
[Sum SQKey],
,
ASC,
DENSE
)
)
If you want to break ties then refer this: