Chapter 7: Project Schedule Planning and Networks Flashcards
What is a network diagram?
Diagram that shows project activities and their logical relationships (the precedence relationships or dependencies among tasks).
It also shows events.
Each activity / task is shown as a box (node), and arrows between them indicate relationships.
What are the two methods for constructing network diagrams?
Activity-on-node (also called the precedence diagramming method)
Activity-on-arrow
What are the 3 dependency relationships?
Mandatory: sequence cannot be reversed; dependency cannot be eliminated
Discretionary: sequence is matter of choice. Sometimes the discretionary dependency can be eliminated and activities overlapped to speed up the project. This is called fast tracking.
External: factors outside project control.
Define sequential activities and parallel activities.
Sequential activities: activities that have a predecessor-successor relationship.
Parallel activities: two / more independent activities that can be performed at the same time in any order.
What are best practices for creating a Project Network?
- list activities from WBS
- draft before software
- rolling wave planning / progressive elaboration (define high-level and detailed activities progressively)
- use software for accuracy, manually check for errors
- define dependencies before scheduling with Gannt
What is the critical path?
The longest sequence of dependent activities in a project network, determining the minimum project duration.
What is a hammock?
An activity that “spans” multiple other activities. Also known as a summary activity.
Not a critical activity.
True or False: Projects can have more than one critical path.
True.
However, this increases the risk of delays.
Define total slack
How long an activity can be delayed without delaying the project.
Define free slack.
How long an activity can be delayed without affecting its successor.
True or False: When an activity has more than one immediate predecessor, the ES for the activity will be determined by the immediate processor that has the earliest EF.
False.
When an activity has more than one immediate predecessor, the ES for the activity will be determined by the immediate processor that has the LATEST EF.
True or False: Whenever we encounter an activity that has multiple immediate successors, it is the EARLIEST LS of the immediate successors that determines the activity’s LF.
True.
Why is it vital to know the critical path? (4)
It identifies the longest sequence of dependent tasks, which determines the shortest possible project duration.
It acts as a frame of reference as to which tasks, if delayed, will affect the whole project, making the critical path crucial for timeline management.
It helps to prioritize resources and monitor efforts on tasks that directly affect project completion.
It allows better decision-making and risk management, as project managers can focus on preventing delays where it matters most.
Define slack.
The amount of allowable deviation between the latest an activity must take place and the earlies it can take place.
In general, when do non-critical activities take place to preserve slack and minimize the risk of non-critical activities delaying the project)?
As early as possible, if there are sufficient resources.
Why is it beneficial to know the free slack?
Managers can readily identify activities where slippages immediately impact other activities.
Many activities are scheduled to start ASAP, and resources are booked to be available on these dates. If an activity is delayed, it can delay other activities and disrupt the schedule.
Such delays can extend the period over which are needed, which can lead to cost overruns.
What is the effect of the project due date?
If target date is LATER than expected completion date:
- result is increasing total slack for every activity in project, even on critical path.
If target date is EARLIER than expected completion date:
- total slack times everywhere in project will be reduced (by difference between target date and completion date).
- activities along critical time will have negative slack times
What are 4 common scheduling issues?
1) resource constraints
2) cash flow limitations
3) risk of change
4) logistics
True or False: External factors like resources, cash flow, and logistics must be considered in project scheduling.
True
What is the difference between a resource-constrained project and a time-constrained project?
Resource-constrained: resources are limited; project completion date is determined by availability of resources.
Time-constrained: project completion date is fixed; resources must be found to meet that date.
Define the following:
1) Resource allocation.
2) Workload
3) Resource loading.
1) Assigning one / more resources to activity or project.
2) Amount of work imposed on a resource. Always from the perspective of the particular resource.
3) The amount of a particular resource needed to conduct all the activities in a project. From perspective of project.
In a matrix organization, the … are responsible for ensuring that each worker’s time is well utilized, and their workload does not exceed a recommended maximum.
functional managers
What are two methods for adjusting schedules to create a smoother workload?
1) Time-constrained levelling
- ensures steady use of resources over time
- activities may be delayed slightly to balance workloads.
2) Resource-constrained levelling
- when resources are strictly limited, tasks must be rescheduled.
- critical chain analysis might be needed.
True or False: Once an “activity” has been defined in the WBS, it cannot be arbitrarily “split” later on.
True.
What are 3 techniques for handling resource constraints?
1)
splitting activities
- large tasks divided to fit resource availability.
2) multitasking & handover points
- different teams handle different phases of a task
- prevents bottlenecks and speeds up execution.
** Multitasking, wherein work is stopped and then resumed, should not be confused with work that continues uninterrupted but has multiple handover points.
3) Prioritizing critical resources
- focus on high-priority tasks / resources first
- avoid unnecessary delays by scheduling efficiently.
True or False: It is impossible to completely level the load for all resources at once.
True
“The best levelling results arise from applying the scheduling equivalent of the ‘Pareto optimum’”.
Explain what is meant by this statement.
Schedule activities in the best interests of the project while trying to minimize the number of conflicts and problems in the departments and contractors that supply the resources.
What are 4 strategies for managing resource constraints?
1) Delay non-critical activities.
2) Substitute resources.
3) Restructure tasks.
4) Reassign high-demand resources to avoid bottlenecks.
In resource levelling, the focus differs from time-constrained resource levelling because the issue is the resource’s maximum requirement, not its loading variability. In addition to levelling of resources, what does this involve?
Rescheduling jobs or delaying them until the resources become available.
