SAP Note 10539 - Form average for statistical ratios only to period 12.

Symptom

If a report evaluates statistical ratios, they are averaged using the periods specified in the report. This can cause problems if the report also displays data from special periods, for example, for period 13 in CO. In this case, the statistical ratios are also averaged using the special periods; this is not normally required.

Cause and prerequisites

There is no special processing for special periods in Report Writer.

Solution
As of Release 2.1, you can define a report using formula variables for
the period which means that special periods are not taken into account
when averaging the periods.

Example from CO:

A report uses the value variable 1PERIB for the to-period.
The report displays both costs and statistical ratios.
You then create a formula variable ZPERBS (transaction GS01) that
calculates the value of the period as follows:
If the value of 1PERIB is greater than 12, then ZPERBS = 12,
otherwise ZPERBS = 1PERIB. The respective formula in the definition
of variable ZPERBS is:

IF '1PERIB' > 12 THEN 12
ELSE '1PERIB'

In the report definition, the variable 1PERIB must now be assigned to
the costs and the variable ZPERBS must be assigned to the statistical
ratios. Since ZPERBS is derived from the variable 1PERIB, ZPERBS is
automatically set as an internal variable. When the report is executed,
only an input field for 1PERIB appears on the selection screen. If
special period 13 is now entered, period 12 is taken for ZPERBS.

Key word: REPORT WRITER

Additional key words

CO Reports, STAGR, Statistical Ratios