Calculated Measure, Member or a Query Calculation?

I posted previously about calculated members, but until recently, I never really understood when to use a calculated measure, a calculated member or a query calculation when building a report. By chance, I had the opportunity to bring this up to an IBM Cognos employee and was delighted to learn the following:

• Use Calculated Member or Calculated Measure for dimensional reports where the expression is a member or a tuple-based (as opposed to property-based) value expression.

• Use Calculate Measure if you intend it to behave like measure (or to replace a measure). In this case, the value expression must not depend on the current measure context.

• Use Calculate Member if you intend it to behave like measure (or to replace a measure). In this case, you must choose a hierarchy. The value expression must not depend on the current context in this hierarchy.

• Use Set Expression for set expressions. In this case, you must choose a hierarchy. The set expression must contain only members in this hierarchy.

Finally, use Query Calculation in all other cases.

Case Expression in Report Studio

Based on a reporting requirement I was asked to present data grouped in year range categories, (e.g. <2000, 2000-2005, 2006-2009, >2009...). The "search case" expression met my objective.

The syntax looks something like this:

case
WHEN [year] < 2000 THEN ("category 1")
WHEN [year] < 2006 THEN ("category 2")
WHEN [year] < 2009 THEN ("category 3")
WHEN [year] > 2009 THEN ("category 4")
...
end

Notice that within the case expression I started with the lessor value (2000) and followed up to the top value. I could have also used an IF ... THEN statement but my feeling is that is it would look quite cluttered.