As your original code is
Public StrTier1, StrTier11 As String
StrTier1 = "Category"
StrTier11 = "category"
are you trying to create constants? If so you would use CONST.
Public Const StrTier1 as String = "Category"
Public Const StrTier11 as String = "category"
In this case I'd use C_Tier1 and C_Tier11 so you know your dealing with a C
onstant that you added.