Burke (2007) states that the timing of a project is determined using forward pass and backward pass.
Forward Pass (FP) allows us to determine the Earliest Start Time (EST) and Earliest Finish Time (EFT).
Appendix 1 – sample calculation
Same goes for backward pass which allows us to determine the Latest Start Time (LST) and Latest Finish Time (LFT).
Appendix 2 – sample calculation
(Field, M. and Killer, L. (2007)p.194) states that total float can be determined by deducting either EST and duration(DUR) from LFT or EFT from LFT.
The time of activity that can be delayed without any affect in the whole project completion time is total float.
1.3. Project Duration and Critical Path
By addition, the number of the days which are needed for every activity on critical path can be determined as project duration. For Vobien Ltd , the project duration is 50 days.
Critical path are those node which have zero float and cannot be delay or early in their activity of time. According to Field and Keller (1998),”Critical Path is normally easily spotted as they pass through nodes with same earliest and latest time.”
For Vobien Ltd, the critical path is A B C F G K L M N O Q R
1.4 The earliest date which the project could be completed is on Friday 20th September 2013 when the date is calculated by deducting the weekends (i.e. Saturday and Sunday) and continuing to count of 50 days from the Monday 15th July 2013.
1.5. The reasons
a) If there is delay by 1 day on activity E, it doesn’t effect on completion time of project since it doesn’t lies in critical path.
b) Same as activity E, activity P doesn’t lies in critical path therefore will have no effect on completion time of project while delay by 2 days.
c) If the activity Q is completed 1 day early then the whole project will be finish 1 day earlier which will be total of 49 days.
1.6. The limitation of Network Diagram * Costly