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CH9: Reducing Project Duration - Coggle Diagram
CH9: Reducing Project Duration
Learning Objectives
09-01 Understand the different reasons for crashing a project.
09-02 Identify the different options for crashing an activity when resources are not constrained.
09-03 Identify the different options for crashing an activity when resources are constrained.
09-04 Determine the optimum cost-time point in a project network.
09-05 Understand the risks associated with compressing or crashing a project.
09-06 Identify different options for reducing the costs of a project.
9.1 Rationale for Reducing Project Duration
Crash
is a term that has emerged in the project management lexicon for
shortening the duration of an activity or a project
beyond when it normally can be done.
Reasons for attempting to reduce the duration of a project are:
Time-to-market pressures
Unforeseen delays
Incentive contracts
(bonuses for early completion)
Imposed deadlines
and
contract commitments
Overhead costs
Pressure to reassign resources
to other projects
9.2 Options for Accelerating Project Completion
Resources Are Not Constrained
Add resources
Outsource project work
Schedule overtime
Establish a core project team
Do it twice—fast and correctly
Resources Are Constrained
Improve project team efficiency
Fast tracking
Use critical-chain management
Reduce project scope
Compromise quality
9.3 Project Cost-Duration Graph
Explanation of Project Costs
Project Indirect Costs
Are costs that
cannot be associated with any particular work package or activity.
Examples are overhead costs such as supervision, administration, consultants, and interest.
Are costs that vary directly with time
Project Direct Costs
Are costs that
assigned directly to a work package and activity
Examples are labor, materials, equipment, subcontractors.
Represent
normal costs
(low-cost, efficient methods for a normal time).
9.4 Constructing a Project Cost-Duration Graph
The project cost-duration graph is used to compare additional cost alternatives for benefits.
Three major steps are required to construct a project cost-duration graph:
1.Find
total direct costs
for selected project durations.
2.Find
total indirect costs
for selected project durations.
3.Sum direct and indirect costs for these selected durations.
Determining the Activities to Shorten
Which activities to shorten?
Look for
critical activities
that can be shortened with the
smallest increase in cost per unit of time.
Assumptions:
1.The cost-time relationship is
linear
.
2.
Normal time
assumes low-cost, efficient methods to complete the activity.
3.Crash time represents a
limit
—the greatest time reduction possible under realistic conditions.
4.
Slope
represents cost per unit of time.
5.All accelerations must occur
within the normal and crash times
.
Activity Graph實例
Cost-Duration Trade-off Example實例
Summary Costs by Duration實例
Project Cost-Duration Graph實例
9.5 Practical Considerations
Using the project cost-duration graph
Crash times
Linearity assumption
Choice of activities to crash revisited
Time reduction decisions and sensitivity
9.6 What If Cost, Not Time, Is the Issue?
Commonly used options for cutting costs are:
Reduce project scope
Have
owner
take on more responsibility
Outsource
project activities or even the entire project
Brainstorm
cost savings options
