PROJECT MANAGEMENTPROJECT MANAGEMENTApproachesApproaches

By- Rahul Jain

Plan your work first…..then work your plan

Network analysis

Network analysis is the general name given to certain specific techniques which can be used for the planning, management and control of projects.

One definition of a project:

“A project is a temporary Endeavour undertaken to create a "unique" product or service”

HistoryHistory Developed in 1950’s CPM by DuPont for chemical plants PERT by U.S. Navy for Polaris missile

PERT was developed by the US Navy for the planning and control of the Polaris missile program and the emphasis was on completing the program in the shortest possible time. In addition PERT had the ability to cope with uncertain activity completion times (e.g. for a particular activity the most likely completion time is 4 weeks but it could be anywhere between 3 weeks and 8 weeks).

CPM was developed by Du Pont and the emphasis was on the trade-off between the cost of the project and its overall completion time (e.g. for certain activities it may be possible to decrease their completion times by spending more money - how does this affect the overall completion time of the project?)

CPM - Critical Path MethodCPM - Critical Path Method

Definition: In CPM activities are shown as a network of precedence relationships using activity-on-node network construction– Single estimate of activity time– Deterministic activity times

USED IN : Production management - for the jobs of repetitive in nature where the activity time estimates can be predicted with considerable certainty due to the existence of past experience.

PERT - PERT - Project Evaluation & Review TechniquesProject Evaluation & Review Techniques

Definition: In PERT activities are shown as a network of precedence relationships using activity-on-arrow network construction– Multiple time estimates – Probabilistic activity times

USED IN : Project management - for non-repetitive jobs (research and development work), where the time and cost estimates tend to be quite uncertain. This technique uses probabilistic time estimates.

Originated by H.L.Gantt in 1918

Gantt chart

Advantages

- Gantt charts are quite commonly used. They provide an easy graphical representation of when activities (might) take place.

Limitations

- Do not clearly indicate details regarding the progress of activities

- Do not give a clear indication of interrelation ship between the separate activities

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Some keytermsSome keyterms There are several key terms

– Critical Path: The longest time path through the task network. The series of tasks (or even a single task) that dictates the calculated finish date of the project (That is, when the last task in the critical path is completed, the project is completed) The "longest" path (in terms of time) to the completion of a project. If shortened, it would shorten the time it takes to complete the project. Activities off the critical path would not affect completion time even if they were done more quickly.

– Slack Time: The amount of time a task can be delayed before the project finish date is delayed. Total slack can be positive or negative. If total slack is a positive it indicates the amount of time that the task can be delayed without delaying the project finish date. If negative, it indicates the amount of time that must be saved so that the project finish date is not delayed. Total Slack = Latest Start - Earliest Start. By default and by definition, a task with 0 slack is considered a critical task. If a critical task is delayed, the project finish date is also delayed. (Also known as float time )

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DefinitionsDefinitionsYet more key PM terms:

Dependencies: Links between project tasks. There are 3 types of dependencies:

– Causal, where 1 task must be completed before another can begin (have to bake bread before you can make a sandwich)

• critical path schedules are based only on causal dependencies

– Resource, where a task is limited by availability of resources (more bread can be baked by 2 bakers, but only 1 is available)

– Discretionary, optional task sequence preferences that, though not required, may reflect organizational preferences

– Milestone: A significant task which represents a key accomplishment within the project. Typically requires special attention and control.

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DefinitionsDefinitions

More key PM terms:

– Crashing: Shifting resources to reduce slack time so the critical path is as short as possible. Always raises project costs and is typically disruptive – a project should be crashed with caution.

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Project Management Project Management DefinitionsDefinitions

Yet more key PM terms:– Duration: The time it takes for an activity to

be completed, given the planned amount of material, labor and equipment.

– Effort: The amount (not duration) of work required to complete a task. Duration may decrease by adding resources but the effort required will remain the same.

– Scope: A specific definition of what the project does and does not entail. Critical to managing expectations of customers and workers alike.

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An Example of a Logical An Example of a Logical SequenceSequence

Making a simple list of tasksMaking a simple list of tasks Planting trees with

flowers and edging around them – tasks required to complete this project:1. Mark utilities2. Dig Holes3. Buy trees4. Buy flowers5. Plant trees6. Plant flowers7. Buy edging8. Install edging

This list does not reflect time or money

This list does not reflect task relationships

This list is a simple sequence of logical events

This list does not provide an easy project “snapshot”

Hard to see conflicts

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An Example of a Logical An Example of a Logical SequenceSequence

Visual Visual - - Using a PERT Chart (Network Using a PERT Chart (Network Diagram)Diagram)Planting trees with flowers and edging around themPlanting trees with flowers and edging around them

Visual – task relationships are clear – good snapshotVisual – task relationships are clear – good snapshot

Created using RF Flow or Visio

Plant TreesMark Utilities Dig Holes

Buy Flowers

Buy Trees

Buy Edging

FinishStart

2 6

7

8Install EdgingPlant Flowers

5

4

1

3

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An Example of a Logical An Example of a Logical SequenceSequence

Tabular Tabular – – including time and cost dataincluding time and cost dataTask Name Normal Time (Days)

Crashed Time (Days)

Normal Cost($)

Crashed Cost($)

Mark Utilities 3 3 0 0

Dig Holes 2 1 100 200

Buy Trees .5 .5 50 50

Buy Flowers .5 .5 50 50

Plant Trees 2 1 100 200

Plant Flowers 1 .5 50 100

Buy Edging .5 .5 25 25

Install Edging 1 .5 25 50

TOTALS 10 6 400 675

NOTE: Shaded areas are concurrent tasks that are completed along the timeline- they contribute to overall cost but not overall duration

CPM/PERTCPM/PERT

These deficiencies can be eliminated to a large extent by showing the interdependence of various activities by means of connecting arrows called network technique.

Overtime CPM and PERT became one technique

ADVANTAGES:– Precedence relationships– large projects– more efficient

The Project NetworkThe Project Network

Use of nodes and arrows

Arrows An arrow leads from tail to head directionally– Indicate ACTIVITY, a time consuming effort that is

required to perform a part of the work.

Nodes A node is represented by a circle

- Indicate EVENT, a point in time where one or more activities start and/or finish.

Activity on Node & Activity on ArrowActivity on Node & Activity on Arrow

Activity on Node

- A completion of an activity is represented by a node

Activity on Arrow

- An arrow represents a task, while a node is the completion of a task

- Arrows represent order of events

Activity SlackActivity Slack

Each event has two important times associated with it :- Earliest time , Te , which is a calendar time when a event can

occur when all the predecessor events completed at the earliest possible times

- Latest time , TL , which is the latest time the event can occur with out delaying the subsequent events and completion of project.

Difference between the latest time and the earliest time of an event is the slack time for that event

Positive slack : Slack is the amount of time an event can be delayed without delaying the project completion

Critical PathCritical Path

Is that the sequence of activities and events where there is no “slack” i.e.. Zero slack

Longest path through a network minimum project completion time

Benefits of CPM/PERTBenefits of CPM/PERT

Useful at many stages of project management Mathematically simple Give critical path and slack time Provide project documentation Useful in monitoring costs

Questions Answered by CPM & PERTQuestions Answered by CPM & PERT

Completion date? On Schedule? Within Budget? Critical Activities? How can the project be finished early at the least cost?

exampleexampleIllustration of network analysis of a minor redesign of a product and its associated packaging.

The key question is: How long will it take to complete this project ?

For clarity, this list is kept to a minimum by specifying only immediate relationships, that is relationships involving

activities that "occur near to each other in time".

•"What activities must be finished before this activity can start"

•could we complete this project in 30 weeks?

•could we complete this project in 2 weeks?

One answer could be, if we first do activity 1, then activity 2, then activity 3, ...., then activity 10, then activity 11 and the project would then take the sum of the activity completion times, 30 weeks.

“What is the minimum possible time in which we can complete this project ? “

Before starting any of the above activity, the questions asked would be

We shall see below how the network analysis diagram/picture we construct helps us to answer this question.

CRITICAL PATH TAKES 24 WEEKS FOR THE COMPLETION OF THE PROJECT

Limitations to CPM/PERTLimitations to CPM/PERT

Clearly defined, independent and stable activities

Specified precedence relationships Over emphasis on critical paths

Thank you