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Questions and Answers

What was the primary purpose of the Critical Path Method (CPM) when it was first developed?

To identify critical paths in projects (correct)

To develop cost estimation techniques

To analyze and plan small projects

To manage team performance

Which of the following accurately defines the Forward Pass in CPM?

Relying on graphical representation for project duration

Calculating late times for activities

Calculating the earliest start and finish times for each activity (correct)

Establishing resources for high-priority tasks

How is the Early Start (ES) determined in a Predecessor Activity Case?

It is equal to the initial time at project start

It is the maximum of the early finish times of all preceding activities (correct)

It is assigned a fixed value of 1

It is the earliest finish time of the current activity

What type of representation does CPM rely on to depict activities and their relationships?

Graphical representation Signup and view all the answers

What does the term 'Critical Path' in CPM refer to?

The sequence of tasks that cannot be delayed without affecting the project's overall duration Signup and view all the answers

What is the output of the Backward Pass in CPM?

Determining late start and finish times for activities Signup and view all the answers

In which industry was the Critical Path Method initially used?

Automotive Signup and view all the answers

What is the equation used to calculate Early Finish (EF)?

EF = ES + Duration Signup and view all the answers

How is Early Finish (EF) calculated for an activity that has multiple predecessor activities?

EF = Maximum of Early Finish Times of predecessor Activities Signup and view all the answers

What does Late Finish (LF) represent in project scheduling?

The latest possible finish time for an activity Signup and view all the answers

What is the formula for calculating Late Start (LS) for an activity?

LS = LF - Activity Duration Signup and view all the answers

When calculating Early Finish for an activity related to only one other activity, which equation is used?

EF = Start Time + Daj Signup and view all the answers

What is the final activity's Late Finish (LF) in scheduling?

LF = Project end time Signup and view all the answers

In project scheduling, how should Late Finish (LF) be determined for an activity with multiple succeeding activities?

LF equals the minimum of the late start times of succeeding activities Signup and view all the answers

When working on Early Finish calculations, which aspect is considered when multiple predecessor activities are involved?

Maximum of the early finish times of the predecessor activities Signup and view all the answers

To calculate the Early Start (ES) of an activity linked to more than one other activity, which equation applies?

ES = Maximum of Early Finish times of predecessor activities Signup and view all the answers

Study Notes

CPM Historical Background

The Critical Path Method (CPM) was developed in the late 1950s by Morgan, Walker, and Kelley at Dupont Company in Detroit.
CPM's primary purpose was to analyze and plan large projects, specifically for identifying critical paths in the automotive industry.

CPM Definition

CPM is a method for analyzing and planning projects, used to identify critical paths, estimate early/late timings, analyze activity sequence, and prioritize high-priority tasks.
It relies on graphical representation to depict activity sequences and relationships, assisting in estimating project completion durations and identifying the critical path.

Stages of Completing CPM

The CPM is calculated in two stages:
Forward Pass
- Calculates the earliest start (ES) and earliest finish (EF) times for each activity.
- Starts from the project’s beginning date and moves forward through the network diagram, considering activity durations and dependencies.
Early Times types
- Early Start (ES): Earliest possible start time for an activity, determined by the earliest finish time of its preceding activities.
- Early Finish (EF): Earliest possible finish time for an activity, calculated based on its early start time and duration.
Calculating early times
- Initial Activity Case: Early Start (ES) is equal to the initial time (0). Early Finish (EF) is calculated using the equation: EF = ES + Duration.
- Predecessor Activity Case: Early Start (ES) is equal to the maximum of the early finish times of all preceding activities. Early Finish (EF) is calculated using the equation: EF = Maximum of Early Finish Times of predecessor Activities.
- Calculation Method: Begin with identifying the initial activity. For each subsequent activity, calculate the early start and early finish using the above equations. Determine the early start and early finish for all activities sequentially to reach the endpoint.
Early Time Equations
- If an activity is related to more than one activity: the ES of activity J is the maximum of the sum of the EF of predecessors A, B, and C plus their respective durations.
- If an activity is related to only one other activity: the ES of activity J is the sum of the EF of predecessor A plus its duration.
Backward Pass
- Calculates the latest finish (LF) and latest start (LS) times for each activity.
- Starts from the project’s end date and moves backward through the network diagram, considering activity durations and dependencies.
Late Times types
- Late Finish (LF): Latest possible finish time for an activity, determined by the latest start time of its succeeding activities.
- Late Start (LS): Latest possible start time for an activity, calculated based on its late finish time and duration.
Calculating late times
- Final Activity Case: Late Finish (LF) is equal to the project end time. Late Start (LS) is calculated using the equation: LS = LF – Activity Duration.
- Successor Activity Case: Late Finish (LF) is equal to the minimum of the late start times of all succeeding activities. Late Start (LS) is calculated using the equation :LS = Minimum of Late Start Times of Successor Activities – Activity Duration.
- Calculation Method: Start with identifying the final activity. For each preceding activity, calculate the late finish and late start using the above equations. Determine the late finish and late start for all activities sequentially to reach the starting point.
Late Time Equations
- If an activity is linked to more than one other activity from the end: The LF of activity J is the minimum of the LS of all succeeding activities.