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weights in PERT

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streetboy streetboy
User offline. Last seen 11 years 41 weeks ago. Offline
Joined: 22 Jun 2008
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why we use the weights of 1 4 1 in the PERT method? what does Sigma mean?


John Cornish
User offline. Last seen 7 years 11 weeks ago. Offline
Joined: 22 Nov 2007
Posts: 49
Hi Street Boy,

The weighting of 1-4-1 for Optimistic, Most Likely and Pessimistic estimated durations, is based on good research and should be trusted.

X-Pert from Micro Planning International offers Pert Estimating of durations in their version 3.5 released in April 2008.

Pert Estimating allows you to now analyse with any of the duration estimates – running a truly optimistic or pessimistic schedule and even compare the results of those schedules by putting one into an archive. A great way to get a sense of the uncertainty in your projects and develop best case and worst case scenarios.