w4_Estimation of Water Projects Duration Using PERT_Thuraiya
Estimation of Water Projects Duration Using PERT
1-
Problem identification:
Water Projects must meet the Scheduled Commencement
Operational Day as it planned to be on operation to meet the demand at that
day. However, many projects are delivered later that what is scheduled. This blog
studies the most suitable duration for constructing water project.
2-
Feasible Alternatives
Currently we allow the developer to
construct the project in 33 months so the feasible alternatives are:
1-
To keep the period of 33
months.
2-
To agree on the result of
Pert analysis that will be shown in this blog.
3-
Development of the outcome
of the alternatives
PERT (Program Evaluation and Review Technique) is one of the
successful and proven methods among the many other techniques. Using
Pert Technique and based on Historical Data will calculate the most appropriate
duration for the construction of water project.
4-
Selection criteria
To give more confidence duration
estimate with probability higher than <90% based on historical data.
5-
Analysis and Comparison of
the alternatives
The table below shows the duration based on
historical data:
Most Optimistic
|
Most Likely
|
Most Pessimistic
|
27 months
|
33 months
|
44 months
|
To calculate the possibility of duration the following
calculations must be done:
Mean = (27+4*33+44)/6= 34 months
Variance = 44-27= 17/6= 3 months
Standard Deviation= 3*3=9
Using Z table:
P80= (0.8 *Variance) + mean = (0.8 *3) +34=
36.5 months
P90= (1.3*Variance) + mean = (1.3*3) +34=
38 months
6-
Selection of the preferred
alternative
The above results show that we can
construct Water Projects within 36.5 months. However, to be more confident 38
months to be considered when constructing as it has more than 90% probability.
7-
Performance monitoring and
the post evaluation results
The above results can be monitored
by applying it to the next project and measure the duration needed.
8-
References
1-
Giammalvo, P.D (2012). Oman
PMI Certification Prep Course Day 2.
2-
May 16, 2012), NORMAL CURVE POSITIVE
3-
PERT Estimation Technique,
(Visited on 28.11.17)
Great case study but why didn't you go back and look at your HISTORICAL DATA ? You used the term "most suitable"? Did you mean the HISTORICAL AVERAGE for OPWP?
ReplyDeleteToo bad that you didn't take a look at the HISTORICAL DATA and run a Statistical Process Control analysis on it. Throw out any outliers +/- 3 sigma from the mean and then look look to see if there is anything broken to the PROCESS?
http://www.planningplanet.com/guild/gpccar/risk-opportunity-monitoring-and-control Go here and review figures 2-11. There is so much you could do with your historical data not only in terms of time but in terms of cost as well.
I hope you will accept the challenge to do another blog or even a series of blogs using your historical data (cost and time)
BR,
Dr. PDG, Jakarta