

Syntax Errors
Formulas are tested before their values are calculated. An error message will appear if QPR Metrics cannot evaluate a formula due to syntax errors. The name of the element containing at least one erroneous formula is highlighted in red in the Scorecard Navigator and the name of the scorecard containing at least one element with at least one erroneous formula is highlighted in red in the Model Navigator. In addition, the Formula Status is shown on the Series Tab of the Element Properties window.
Values Out of Range
Calculation results which are out of range are reported, as well as nil values if they appear with the standard functions, i.e. functions without the underline suffix.
An expression becomes nil if it contains
•  a missing value or a period, 
•  a measure with unselected value settings, 
•  nonexistent series, or 
•  if the expression contains a wildcard pattern which does not match any element or series. 
The result of an arithmetic operation is nil if at least one of the operands is nil.
Circular References
QPR Metrics does not allow looping calculation chains, i.e. chains where two or more measure values are dependent on each other.