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# Primavera Risk Analysis - Getting the absolute minimum and maximum

3 replies [Last post]
Alireza R
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Joined: 20 Feb 2020
Posts: 2
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Hi all,

I have a very detailed risk analysis for my project (different risks, different uncertainties with different distributions,...). And now I would like to see the "absolute" minimum and maximum end dates.

Ofcourse since Monte Carlo Analysis is based on random iterations, I can never say with certainty what the shortest project duration is (think extremely happy flow, all uncertainties getting the minimum durations). I get the minimum from OPRA but next time I run the simulation I might get a new minimum (or maximum).

I know this defies the purpose of statistical nature of Monte Carlo but I am wondering whether there is an option to first find the extreme values on the both ends of the spectrum and then fill in the between (something like a polygraph, jumping to the both extremes first and then filling the values the fall within those two).

I have tried increasing the iterations to 20000 (higher than 99% confidence level) but this still is not hitting the sweet spots.

any ideas?

br.

AR

## Replies

David Kelly
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Joined: 19 Oct 2004
Posts: 612
No Oracle customers even know that is missing, Vladimir.
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Joined: 5 Feb 2001
Posts: 2639

David,

Spider Project creates optimistic and pessimistic project versions.

Optimistic uses optimistic estimates of project parameters and includes risk events with more than 90% probabilities to occur, pessimistic uses pessimistic estimates of project parameters and includes all risk events.

David Kelly
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Joined: 19 Oct 2004
Posts: 612
As you admit yourself, your question kind of undermines the whole ethos of probabilistic analysis. There are no “deterministically” best and worst dates following a probabilistic analysis. You could choose to calculate and save the 1% and 99% percentiles, and ensure you are using Monte Carlo and not Latin Hypercube sampling, both of which you will find in the Risk Analysis Options.