1. Problem Recognition
This post will estimate the schedule for a maintenance project for fire water pond leakage which posted in my previous blog W3.1. The critical path is civil works for concreting the pond. In similar project the civil engineer is estimating the time required to do such task based on his experience. Even though expert judgments is an acceptable tool to estimate schedule I will incorporate PERT method with P90 will to estimate the time required to complete the critical path.
2. Development the Feasible Alternative
- A combination of Expert judgment and PERT method – based on the time it took to do similar tasks on other projects and based on the experience of civil engineer in similar projects
- PERT – duration based on P95 & P80
- Development of the Outcome for Alternatives
PERT Method calculation is illustrated in below formula:
Where X is the Unknown value, M = Mean, STDv = Standard deviation, P95=1.65 from Z table
Solution of formula 1 in Table -1
4. Selection of Criteria
The critical path for this project is the civil works and there will be some activities before and after starting the critical path. The most accurate method which reflects actual will be selected.
5. Analysis and Comparison of the Alternative
From Table-1 it can be seen that the critical path will 8 weeks with probability of 95% and 7.4 weeks with 80% probability. The results are very near.
6. Selection of the Preferred Alternative
The preferred is P95 and it gives 8 weeks estimation for the civil works.
7. Performance Monitoring and the Post Evaluation of Result
In coming blogs work break down structure for critical path will be established and schedule of the project as will
- W2_Murtadha_Schedule Estimation Analysis retrieved July 29th 2014 https://pmioman14.wordpress.com/2014/06/12/w2_murtadha_schedule-estimation-analysis/
- Six Methods for the Estimation of Activity Duration in Project Management retrieved July 29th 2014 http://smallbusiness.chron.com/six-methods-estimation-activity-duration-project-management-41782.html
- Estimating Time Accurately retrieved July 29th 2014 http://www.mindtools.com/pages/article/newPPM_01.htm