Activity Network Diagram

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Activity Network Diagram

• Brian McAluney
• OISM 470W
• PowerPoint Training Presentation

2
Overview

• Definition of an Activity Network Diagram
• History
• Basic Terms
• How can it be used in your organization?
• How the diagram works
• Example
• Activity Network Diagram Exercise
• Summary

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Definition of an Activity Network Diagram

• Also known as the Program Evaluation Review
  Technique (PERT) or Critical Path Diagram
• Tool used to control the length of projects
• Takes into account many aspects of projects
  task times, slack times, critical tasks, etc.

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Definition of an Activity Network Diagram (cont.)

• Designed for research and development-type
  projects
• Determines a probability distribution for a
  project

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History

• Developed by the U.S. Department of Defense
• First used as a management tool for military
  projects
• Adapted as an educational tool for business
  managers

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Basic Terms

• Basic Vocabulary of the PERT Diagram
• Activity part of the project represented by an
  arrow or line
• Best Estimate(B) earliest completion time
• Critical path(CP) the most time consuming path
  through the diagram with no slack time
• Earliest Start Time(EST) earliest possible time
  for an activity to begin
• Network the project shown graphically
• Most likely estimate(M) length of time probably
  needed

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Basic Terms (cont.)

• Expected Time(ET) the average duration time
• Event represents the start or finish of one or
  more events (shown as a circle, square, or other
  symbol)
• Latest Start Time(LST) latest time an activity
  can begin and still be completed before the next
  activity
• Slack Time latest start time minus earliest
  start time for an activity
• Worst estimate(W) pessimistic time estimate

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How can it be used in your organization?

• Brainstorm ideas of where activity network
  diagrams could be utilized in your business
  practices

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How can it be used in your organization?

• Finding minimum completion times
• Determining maximum completion times
• Value of time for each step in the project

• Assigning specified times for parts of the
  project
• Creates a realistic schedule for the company

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How the diagram works

• Basic Rules
• All preceding activities must be completed before
  the project can begin
• The arrows represent the logical precedence of
  the project

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How the Diagram Works (Cont.)

• Procedure for development
• Identify all activities and relationships among
  them
• Sketch the diagram
• Estimate the times for each activity, or node, in
  the diagram
• Determine the critical path
• Evaluate the diagram for milestones and target
  dates in the overall project

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Example

• Activity Network Diagram

A
D
C
F
B
E
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Exercise

• Given the following formula, data, and diagram,
  determine the critical path and the expected time
  of the project.
• Time is represented in days
• ET 4(M) 1(B) 1(W) / 6
• A 2, B 3, C 1, D 4, E 3, F 2, G 2,
  H 1, and I 3

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Exercise (cont.)
A
D
G
C
F
I
B
E
H
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Begin the Analysis

• Remember your steps for PERT diagrams
• Using the given diagram, list all the steps
• Determine task times
• Determine relationships between the tasks

• Find the earliest start time
• Find the latest start time
• Determine slack and the critical path

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Summary

• Review the exercise
• Advantages of PERT
• Disadvantages of PERT
• Odds and Ends

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Review the Exercise

• Did you arrive at the correct answer?
• Do these answers make sense?

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Advantages of PERT Diagrams

• Projecting plans before they begin
• Helps to separate planning and scheduling
  functions of a project
• Controls projects
• Clarifies maintenance of the plan
• Shows dependency of different aspects of the
  project

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Advantages of PERT Diagrams

• Allows for concentration on the steps themselves
  and not the time required for each
• Represents a realistic schedule
• Focuses attention on critical aspects of the plan
• Changes can be made easily in the project

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Disadvantages of PERT Diagrams

• Cannot handle all specific problems that arise in
  each step of the project
• Different graphical representations can be made
  easier in other types of control processes

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Odds and Ends

• Activity Network Diagrams have many more
  advantages than disadvantages
• They are used in all types of businesses
• The topics that were covered should act as the
  key in helping you lead your company in their
  next business project

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Works Cited

• Bedworth, David D. and James E. Bailey.
  Integrated Production Control Systems. New
  York John Wiley Sons, 1987.
• PERT. Internet. http//www.uwf.edu/coehelp/st
  udentaccount s/rnew/perthome.html. 12 February
  2001.
• Stamatis, D.H. TQM Engineering Handbook. New
  York Marcel Decker, Inc. , 1997.