Chapter 14 Flashcards
What is a “Project”?
A temporary endeavor undertaken to create a unique product or service.
Project Characteristics
Unique item or event - often a single unit.
Often located in one place. The unit does not move during production.
Resources are brought to the project.
May be of any size, although we tend to focus on large projects.
Project Management
Planning
Scheduling
Control
Planning
Identify the project customer
Establish the end product or service
Set project objectives
Estimate total resources and time required
Decide on the form of project organization
Make key personnel appointments
Define major tasks required
Establish a budget
Scheduling
Develop a detailed work breakdown structure
Sequence tasks in proper order
Estimated time required for each task
Develop a start/stop time for each task
Develop detailed budget for each task
Assign people to tasks
Control
Monitor actual time, cost, and performance
Compare planned to actual figures
Determine whether corrective action is needed
Evaluate alternative corrective actions
Take appropriate corrective action
Project Scheduling Methods
Network Methods
Gantt Charts
Network Methods
Project shown as a network (diagram)
Shows precedence relationships
More complex and costly than Gantt charts
Gantt Charts
Project shown as a bar chart
Does not show precedence relationships
Visual & easy to understand
Network Approaches
Constant Time Method (CTM)
Program Evaluation and Review Technique (PERT)
Critical Path Method (CPM)
Constant-Time Method (CTM)
Activity times are assumed to be constant
Program Evaluation and Review Technique (PERT)
Activity times are assumed to be stochastic
Optimistic, most likely, and pessimistic time estimates are used to compute a single expected time for each activity
Expected activity times are used in the scheduling process exactly as the constant times are used in CTM
Probabilistic project completion time estimates can be estimated
Network Approaches
Activity-on-arrow vs. activity-on-node conventions
“Dummy” activities
An “event” is the completion and/or beginning of one or more activities
Critical Path
A path is a sequence of connected activities running from the source node to the sink node
Slack Times
Slack time is the amount of time a path may be delayed without delaying the project
Paths not on the critical path have slack
Optimistic Time Estimate (To):
A time that the activity would have a 1% chance of meeting or bettering.
Total Slack =
LS-ES = LF-EF
The critical path is the path in the network that is estimated to require
the most time to complete (length of the critical path is equal to the project completion time)
A project cannot be expected to be completed in less time than
time required by the critical path.
Any delay on the critical path will likely result in
the project completion being delayed (unless “corrective action” is taken or the time is “made up” elsewhere)
Pessimistic Time Estimate (Tp):
A time that the activity would have a 99% chance of meeting or bettering.
Most Likely Time Estimate (Tm):
The most realistic estimate of the time required to perform the activity (the mode).
With PERT (unlike with the constant time method), the probability of completing a project by a specified deadline
can be estimated.
Scheduling is only part of a
complete approach to project management
Advantages of Network Approaches
Forces the manager to consider the parts of the whole and how they fit together
Pinpoint critical and “near critical” paths
Control tool
Disadvantages of Network Approaches
Many managers already know from experience the information that the formal technique provides
Takes away some of manager’s power (as the sole source of planning)
Subjectivity of time estimates:
“Padded” times to provide “cushion” for evaluation
Manipulation of times to avoid being on critical p
Limitations of Network Approaches
All activities are assumed to be successful on the first try (no failures/re-starts)
Preceding event must be “realized” before succeeding activities can begin
“Near critical” paths with large time variances
Distribution of activity times is assumed to approximate the Beta distribution
Critical Path Method (CPM)
Objective is to reduce the amount of time the project is expected to take to be completed
Assumes that activity times can be reduced by adding additional resources
Focus is on reducing the time required to complete the critical path activities
Within the critical path activities, “crash” those activities that are least costly to crash.
If still “tied” (actually not a part of the formal technique):
If risk averse - crash early in the critical path
If risk taker - wait to verify crashing is needed
Objectives and trade offs of projects
Stay within budget
Meet the deadline
Meet the specifications
