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Distribution Models in Pertmaster

2 replies [Last post]
Daniel Situmorang
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I’m doing a risk assessment of a schedule using Pertmaster and got stuck when trying to determine which distribution model would fit the activities. Does anyone have a hint how to determine which would be the suitable model? (i.e BetaPart, Triangular, Trigen etc). By default Pertmaster suggested to use Triangular.

Daniel T. S


Chachrist Srisuwa...
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Joined: 9 Jan 2007
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Find a video clip about the activity, and timing them for (maybe) 30 cycles at least. Then use software such as StatFit to analyze the raw data in order to obtain distribution with its parameter(s).
If you can get the recorded time for the activities of interest, i am willing to help you determine distribution.
Good Luck :)
Peter Holroyd
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Joined: 6 Jun 2005
Posts: 112
Don’t get to hung up on the minute detail. The fact you are doing a schedule duration risk assessment is good.
I usually use triangle (95/115)for D & E, rectangular (100/120) for materials & equipment and revert to triangular for construction (95/135) -this is biased to pessimism against "normal" values cause thats reality

Don’t forget you are only modelling duration variances - use other values. The duration is a function of so many variables.

Try the next step and add in the risks to the analysis!!