CASE
WHEN [Measures].[Issues resolved] > 0
AND [Measures].[Total resolution workdays] > 1
AND [Issue].[Priority].CurrentMember IS [Issue].[Priority].[Critical]
THEN [Measures].[Total resolution workdays] / [Measures].[Issues resolved]
WHEN [Measures].[Issues resolved] > 0
AND [Measures].[Total resolution workdays] > 5
AND [Issue].[Priority].CurrentMember IS [Issue].[Priority].[Major]
THEN [Measures].[Total resolution workdays] / [Measures].[Issues resolved]
WHEN [Measures].[Issues resolved] > 0
AND [Measures].[Total resolution workdays] > 20
AND [Issue].[Priority].CurrentMember IS [Issue].[Priority].[Minor]
THEN [Measures].[Total resolution workdays] / [Measures].[Issues resolved]
END