International Journal of Business and Economics

International Journal of Business and Economics
Volume 20, No. 2

September, 2021
The Impact of Changing the Expected Time and Variance
Equations of the Project Activities on The Completion
Time and Cost of the Project in PERT Model
Moayyad Al-Fawaeer
Al-Zaytoonah University of Jordan, P.O.Box 130, Amman 11733, Jordan.
Abdul Sattar Al-Ali
Senior Member IIE, MCSCMP, EFQM, 2450 Falkland Cres, Oakville, Ontario, L8M 4Y3, Canada.
Mousa Khaireddin
Khawarizmi University Technical College, 36 Mirza Wasfi St. Amman, Jordan.
Scheduling is one of the most important tools used in project management, and Programming Evaluation Revision Technique (PERT) is one of the methods used in project scheduling. PERT depends on identifying three possible times for any activity: optimistic, pessimistic, and the most likely. Using these three times, the expected time to end the activity and then the critical path of the project, as well as the activity variance, and then the project standard deviation is calculated by offering different weights for these three times. Therefore, this study aimed to suggest the use of equal weights for these times in calculating both the expected time to complete the activity as well as its variance, in order to know the effect on the completion time of project, the standard deviation of the project, as well as the cost of project crashing. To do that the both models usual PERT model and the proposed model were applied on three real construction projects. The results revealed that the proposed model (equal time weights) has a positive impact on the project crashing cost if required, but the results also revealed a negative impact of applying the proposed model on the project completion time (longer critical path), and on the standard deviation of the project.
Keywords:PERT Model Critical Path, Variance, Project Standard  Deviation, Project Cost, Project Crashing Cost.
JEL Classifications:L7, L74, N6.