Example one features a general purpose CPM program that also offers support for the three time estimate (PERT) approach. Several products have a PERT capability, but we will look at Project Scheduler 8, from Scitor, because of some of its special PERT features.
In PS8, we can activate the PERT mode and add a PERT DUR column to the task table. We can enter the three time estimates, and (in a special PS8 feature) adjust the weighting factors. In Figure 6.3a, we can see that (using the traditional 1/4/1 weighting) the calculated project duration is 21.33 days (vs. the 20 days using the single estimates).
By adjusting the weight factors, we can calculate various degrees of optimism or confidence. Using a 1/0/0 weighting, we calculate the project using only the optimistic durations. In this case we can say that the best possible project end date is 10/16 or 16 days. By changing to a 0/0/1 weighting (all pessimistic) we can project a worst case of 11/1 or 32 days.
Another option is to deliberately add time contingency, by giving more weight to the pessimistic dates. In the model above, setting the weight factors to 1/4/5
Figure 6.3a PERT Mode in Project Scheduler 8 (Scitor)
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0d will generate a 25.6 day schedule. While PS8 has this unusual capability to select the weighting factors, it does not provide support for statistical analysis and probability of various end dates (normally expected in a PERT-type program). Our next two examples do.
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What you need to know about… Project Management Made Easy! Project management consists of more than just a large building project and can encompass small projects as well. No matter what the size of your project, you need to have some sort of project management. How you manage your project has everything to do with its outcome.