Measure or Calculated Column

Hi ArchStanton,

I would suggest to create a separate table like this 

AgeBands =
DATATABLE(
"AgeGroup", STRING,
"MinDays", DOUBLE,
"MaxDays", DOUBLE,
{
{"0-3 Mths", 0, 91.3},
{"3-6 Mths", 91.3, 182.6},
{"6-9 Mths", 182.6, 274},
{"9-12 Mths", 274, 365.25},
{"12-15 Mths", 365.25, 457},
{"15-18 Mths", 457, 547.9},
{"18-21 Mths", 547.9, 639.19},
{"21-24 Mths", 639.19, 730.5},
{"24-27 Mths", 730.5, 821.9},
{"27-30 Mths", 821.9, 913.2},
{"30-33 Mths", 913.2, 1004.5},
{"33-36 Mths", 1004.5, 1095.8},
{"36-39 Mths", 1095.8, 1187.1},
{"39-42 Mths", 1187.1, 1278.4},
{"42-45 Mths", 1278.4, 1369.7},
{"45-48 Mths", 1369.7, 1461},
{"48-51 Mths", 1461, 1552.4},
{"51-54 Mths", 1552.4, 1643.7},
{"54-57 Mths", 1643.7, 1735},
{"57-60 Mths", 1735, 1826.3},
{"60+ Mths", 1826.3, 99999}
}
)

and create a relationship with your actual table and use this in your visual, you can filter 0-3mth, 3-6mth age groups from the filter pane.

Hi ArchStanton,

Update your measure like this 

CasesInAgeBand =
SUMX (
AgeBands,
VAR CurrentBandMin = AgeBands[MinDays]
VAR CurrentBandMax = AgeBands[MaxDays]
RETURN
CALCULATE (
COUNTROWS ( 'Cases' ),
'Cases'[CaseLengthDays] >= CurrentBandMin,
'Cases'[CaseLengthDays] < CurrentBandMax
)
)