Activity Network DiagramActivity Network Diagram

Brian McAluneyBrian McAluney

OISM 470WOISM 470W

PowerPoint Training PowerPoint Training PresentationPresentation

OverviewOverview

• Definition of an Activity Network DiagramDefinition of an Activity Network Diagram• HistoryHistory• Basic TermsBasic Terms• How can it be used in your organization?How can it be used in your organization?• How the diagram worksHow the diagram works• ExampleExample• Activity Network Diagram ExerciseActivity Network Diagram Exercise• SummarySummary

Definition of an Definition of an Activity Network DiagramActivity Network Diagram

• Also known as the Program Also known as the Program Evaluation Review Technique Evaluation Review Technique (PERT) or Critical Path Diagram(PERT) or Critical Path Diagram

• Tool used to control the length of Tool used to control the length of projectsprojects

• Takes into account many aspects Takes into account many aspects of projects: task times, slack of projects: task times, slack times, critical tasks, etc.times, critical tasks, etc.

Definition of an Definition of an Activity Network Diagram Activity Network Diagram (cont.)(cont.)

• Designed for research and Designed for research and development-type projectsdevelopment-type projects

• Determines a probability Determines a probability distribution for a projectdistribution for a project

HistoryHistory

• Developed by the U.S. Department Developed by the U.S. Department of Defenseof Defense

• First used as a management tool First used as a management tool for military projectsfor military projects

• Adapted as an educational tool for Adapted as an educational tool for business managersbusiness managers

Basic TermsBasic Terms

Basic Vocabulary of the PERT Diagram:Basic Vocabulary of the PERT Diagram:• Activity – part of the project represented by an Activity – part of the project represented by an

arrow or linearrow or line• Best Estimate(B) – earliest completion timeBest Estimate(B) – earliest completion time• Critical path(CP) – the most time consuming Critical path(CP) – the most time consuming

path through the diagram with no slack timepath through the diagram with no slack time• Earliest Start Time(EST) – earliest possible time Earliest Start Time(EST) – earliest possible time

for an activity to beginfor an activity to begin• Network – the project shown graphicallyNetwork – the project shown graphically• Most likely estimate(M) – length of time Most likely estimate(M) – length of time

probably neededprobably needed

Basic Terms (cont.)Basic Terms (cont.)

• Expected Time(ET) – the average duration timeExpected Time(ET) – the average duration time• Event – represents the start or finish of one or Event – represents the start or finish of one or

more events (shown as a circle, square, or more events (shown as a circle, square, or other symbol)other symbol)

• Latest Start Time(LST) – latest time an activity Latest Start Time(LST) – latest time an activity can begin and still be completed before the can begin and still be completed before the next activitynext activity

• Slack Time – latest start time minus earliest Slack Time – latest start time minus earliest start time for an activitystart time for an activity

• Worst estimate(W) – pessimistic time estimateWorst estimate(W) – pessimistic time estimate

How can it be used in your How can it be used in your organization?organization?

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

How can it be used in your How can it be used in your organization?organization?

• Finding minimum Finding minimum completion timescompletion times

• Determining Determining maximum maximum completion timescompletion times

• Value of time for Value of time for each step in the each step in the projectproject

• Assigning Assigning specified times specified times for parts of the for parts of the projectproject

• Creates a realistic Creates a realistic schedule for the schedule for the companycompany

How the diagram worksHow the diagram works

Basic Rules:Basic Rules:

• All preceding activities must be All preceding activities must be completed before the project can completed before the project can beginbegin

• The arrows represent the logical The arrows represent the logical precedence of the projectprecedence of the project

How the Diagram Works How the Diagram Works (Cont.)(Cont.)

Procedure for development: Procedure for development:

1.1. Identify all activities and relationships Identify all activities and relationships among themamong them

2.2. Sketch the diagramSketch the diagram3.3. Estimate the times for each activity, or Estimate the times for each activity, or

node, in the diagram node, in the diagram 4.4. Determine the critical pathDetermine the critical path5.5. Evaluate the diagram for milestones and Evaluate the diagram for milestones and

target dates in the overall projecttarget dates in the overall project

ExampleExample

Activity Network DiagramActivity Network Diagram

A

B

C

E

D

F

ExerciseExercise

Given the following formula, data, Given the following formula, data, and diagram, determine the critical and diagram, determine the critical path and the expected time of the path and the expected time of the project.project.

Time is represented in daysTime is represented in daysET = 4(M) + 1(B) + 1(W) / 6ET = 4(M) + 1(B) + 1(W) / 6A = 2, B = 3, C = 1, D = 4, E = 3, F A = 2, B = 3, C = 1, D = 4, E = 3, F = 2, G = 2, H = 1, and I = 3= 2, G = 2, H = 1, and I = 3

Exercise (cont.)Exercise (cont.)

A

B

C

D

E

F

G

H

I

Begin the AnalysisBegin the Analysis

Remember your Remember your steps for PERT steps for PERT diagrams:diagrams:

Using the given Using the given diagram, list all the diagram, list all the stepssteps

Determine task Determine task timestimes

Determine Determine relationships relationships between the tasksbetween the tasks

Find the earliest Find the earliest start timestart time

Find the latest Find the latest start timestart time

Determine slack Determine slack and the critical and the critical pathpath

SummarySummary

Review the exercise Review the exercise Advantages of PERT Advantages of PERT Disadvantages of PERTDisadvantages of PERT Odds and EndsOdds and Ends

Review the ExerciseReview the Exercise

Did you arrive at the Did you arrive at the correct answer?correct answer?

Do these answers make Do these answers make sense?sense?

Advantages of PERT Advantages of PERT DiagramsDiagrams

• Projecting plans before they beginProjecting plans before they begin• Helps to separate planning and Helps to separate planning and

scheduling functions of a projectscheduling functions of a project• Controls projectsControls projects• Clarifies maintenance of the plan Clarifies maintenance of the plan • Shows dependency of different Shows dependency of different

aspects of the projectaspects of the project

Advantages of PERT Advantages of PERT DiagramsDiagrams

• Allows for concentration on the Allows for concentration on the steps themselves and not the time steps themselves and not the time required for eachrequired for each

• Represents a realistic scheduleRepresents a realistic schedule• Focuses attention on critical Focuses attention on critical

aspects of the planaspects of the plan• Changes can be made easily in the Changes can be made easily in the

projectproject

Disadvantages of PERT Disadvantages of PERT DiagramsDiagrams

• Cannot handle all specific Cannot handle all specific problems that arise in each step of problems that arise in each step of the projectthe project

• Different graphical representations Different graphical representations can be made easier in other types can be made easier in other types of control processes of control processes

Odds and EndsOdds and Ends

Activity Network Diagrams have many Activity Network Diagrams have many more advantages than disadvantagesmore advantages than disadvantages

They are used in all types of They are used in all types of businessesbusinesses

The topics that were covered should The topics that were covered should act as the key in helping you lead your act as the key in helping you lead your company in their next business project company in their next business project

Works CitedWorks Cited

Bedworth, David D. and James E. Bailey. Bedworth, David D. and James E. Bailey. Integrated Production Control SystemsIntegrated Production Control Systems. . New New York: John Wiley & Sons, 1987.York: John Wiley & Sons, 1987.

““PERT”. Internet. PERT”. Internet. http://www.uwf.edu/coehelp/http://www.uwf.edu/coehelp/studentaccountstudentaccounts/rnew/perthome.htmls/rnew/perthome.html. . 12 February 2001.12 February 2001.

Stamatis, D.H. Stamatis, D.H. TQM Engineering HandbookTQM Engineering Handbook. . New New York: Marcel Decker, Inc. , 1997.York: Marcel Decker, Inc. , 1997.