Whole Value and Exceptional Value accumulate useful information that may not always be visible in the user-interface due to rounding or other simplification. That information and more must be retrievable from the point where values are displayed.
As the various records of business activity are cross-checked, disagreements are sure to arise. Much published information will be in doubt until the nature of the error is determined.
Tracking down a recording error is substantially different than observing the operation of normal business. However, if we turn to completely new observation mechanisms, we loose track of the familiar making for tedious work.
Therefore:
Incorporate mechanisms for the diagnostic tracing of every value in the system. Make every display that rounds or summarizes offer the unprocessed values for inspection.
Normal display: 67% Diagnostic display: 66.6454329
Normal display: 652 MM USD EQV Diagnostic display: 622,456,325.07 USD + 3,624,878,450 JPY + 23,549.54 FRF
Likewise, where rules and formulas have been applied, make these retrievable from the system itself and format them with variable names and the values bound in the particular calculation.
Since the trace will ultimately lead to value entry, make sure you can report the date, time and identity of the source.
Normal display: 22% Diagnostic display: ROR = 22% = internal rate of return P0, P1, CFi P0 = 32,454.55 = market value (1/1/93) P1 = 36,537,39 = market value (12/31/93) CF1 = 354.00 = cash flow (3/15/93, #1000324) CF2 = -400.00 = cash flow (7/31/93, #1000378) CF3 = -100.00 = cash flow (8/30/93, #1000412)
The correction of input errors offers another source for diagnostic information. Prior values and the time and identity of all sources should be available to diagnosis.
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