Page 265 - DMGT521_PROJECT_MANAGEMENT

Project Management

Notes Time Expected (Te)

A Construction Project
Let us start with construction program of a yatch. Being our first venture, we would
prepare a PERT and obtain necessary estimates from designers, yatch builders and
other knowledgeable persons like carpenters, welders and electricians in their respective
fields.
The three estimates, optimistic, most likely and pessimistic, are given in table titled Basic
Question. In the next table Time Expected (Te) has been calculated based on the formula
given previously.
As stated before, PERT uses a "Weighted Average" of three time-estimates to calculate
Time Expected (Te) for a particular task. These estimates are not wild guesses but have
come from reliable sources. When it comes to masonry work, who can better estimate
time required for making a brick wall than an experienced mason.
Various researchers have criticized use of "weighted averages" in time estimates. They
argue that in this way, time would often be underestimated. But whenever one tries to
predict future, one is confronted with many problems. To be realistic, one should make
meticulous efforts and double check every figure.
Once we know the Te for each task, the rest is like CPM i.e. (i) the boxes representing
variou activities would be placed keeping in view the predecesssor and successor activities,
(ii) clear cut linkages shown between the activities, (iii) forward passes made to
workout project duration, (iv) all possible paths identified and (iv) the longest path, being
the Critical Path highlighted with red-line. This has been shown in the net work given
below:

Contd...

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