Hi John,
In Fluor we have not gotten stuck on the statistical terms although I get from your message that it ties into the two (or three if we include schedule contingency) mechanisms that we have for managing contingency.
We make a clear distinction between our "estimating" contingency and event driven contingency. The former is based purely on uncertainties in the estimate and is established using a Monte Carlo Simulation and selecting a P level that our company is comfortable with. This contingency is managed using a rundown (and is expected to be spent and thus run down to zero when the job is complete). I distinguish between rundown (showing your "forecast to complete" contingency against an expected rundown curve) and a drawdown (a curve that forces you to reduce your "forecast to complete" based on achieving specified milestones). I am not sure if this is or could be an accepted definition for rundown vs drawdown? Our preference is a rundown (using this definition) since it helps to stabilize the bottom-line forecast and having a better 'justification' for forecast changes.
We have a second value that is based only on identified risks of events that may or may not happen, and by applying a likelihood of occurrence, an even driven risk contingency is established (again with a Monte Carlo Simulation). This is not reported against a rundown but re-evaluated on at least a quarterly basis. Events that do occur (or are likely to occur) are removed from this simulation and included in our (mitigated) cost forecast. This contingency may have a residual value when job is completed due to remaining risk of liabilities - when all events either occurred or will not happen at all, this contingency value is zero.
Best regards
Anton
Anton van der Steege | FLUOR | Fellow - Global Cost Lead | CCP | anton.van.der.steege@fluor.com
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