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Define a Calculated Measure
You can create a calculated measure to derive new numeric data from regular
measures, other calculated measures, functions, and constants.
You can specify the format for the result, and also explain the calculation in the
Description box on the Measure property sheet, so that your users can see how
the data was derived.
For example, you create a calculated measure for Profit Margin by subtracting Cost
from Revenue and dividing the result by Revenue. You select
0% on the Format
tab, so that the results of your calculated measure are expressed as percentages.
For an item costing 2000 with a revenue of 4000, your users see a Profit Margin of
50%.
After you create a calculated measure, you can control whether the measure is
calculated before or after rollup.
All calculations defined in a cube are performed based on built-in rules of
precedence. Where there are intersecting calculations, the after-rollup calculations
defined for all measures are performed first. These are followed by calculations for
calculated categories, and then by dynamic and regular rollups. This is important
information for your users, who need to understand the results they are seeing in
the intersecting cells of their crosstab reports.
Procedure
1. Click the Measures list to make it active and, from the Edit menu, click Insert
Measure .
2.
In the Measure name box, enter a name for the measure.
The measure name must be unique in the model.
3. Select the Type tab, click Calculated and then click Calculation .
4. In the left pane of the expression editor, expand the Functions and Measures
folders as needed, select each parameter you want to use and click the
right-arrow button to insert it into the
Expression definition box in the right
pane of the editor.
For more information, see “Cognos Transformer Functions” on page 99 and
Appendix F, “IBM Cognos Transformer Expression Editor,” on page 355.
5.
When the expression is complete, click OK .
6. Type or select the other features you want for the measure, such as the
description and format and click
OK .
Your new calculated measure appears in the Measures list.
Define When Measures are Calculated
When you use a calculated measure, you can have the measure calculated before
or after rollup. Values for measures calculated before rollup are based on source
values instead of summed values, and are rolled up separately.
The following table shows the sequence of operations that take place when
calculating measures.
Chapter 5. Modeling Your Key Performance Measures
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