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PROJECT SCHEDULINGCHAPTER 4ME751 ELECTIVE PROJECT MANAGEMENT

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INTRODUCTION A human being normally would

perceive a schedule to be some sort of a time table.

In Project Management, a schedule consists of a list of project terminal elements with an intended start and finish dates.

The project schedule is a calendar that links the tasks to be done with the resources that will do them.

Terminal elements are the lowest elements in a schedule which are not further subdivided.

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ROLE OF SCHEDULING IN PROJECT MANAGEMENT They provide a basis for you to monitor

and control project activities. They help you determine how best to

allocate resources so you can achieve the project goal. 

They help you assess how time delays will impact the project.

You can figure out where excess resources are available to allocate to other projects. 

They provide a basis to help you track project progress.

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SOME RULES OF THE THUMB Organize tasks concurrently to make optimal

use of workforce. Minimize task dependencies to avoid delays

caused by one task waiting for another to complete.

Dependent on project managers intuition and experience.

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INPUTS TO CREATE A PROJECT SCHEDULE Personal and project calendars – Understanding working

days, shifts, and resource availability is critical to completing a project schedule.

Description of project scope – From this, you can determine key start and end dates, major assumptions behind the plan, and key constraints and restrictions. You can also include stakeholder expectations, which will often determine project milestones.

Project risks – You need to understand these to make sure there's enough extra time to deal with identified risks – and with unidentified risks (risks are identified with thorough Risk Analysis).

Lists of activities and resource requirements – Again, it's important to determine if there are other constraints to consider when developing the schedule. Understanding the resource capabilities and experience you have available – as well as company holidays and staff vacations – will affect the schedule.

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INPUTS TO CREATE A PROJECT SCHEDULE (CONTINUED) Project risks – You need to understand

these to make sure there's enough extra time to deal with identified risks – and with unidentified risks (risks are identified with thorough Risk Analysis).

Lists of activities and resource requirements – Understanding the resource capabilities and experience you have available – as well as company holidays and staff vacations – will affect the schedule.

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THE SCHEDULE FORMULADuration= Work÷ Resource Units Duration is the length of working time between

the start and finish of a task.  Work is the amount of effort, measured in time

units (like hours or days), that a resource needs to complete the task. The total work for a task is the sum of all those time units, no matter how many resources are assigned to the task.

Resource Units indicate how much of a resource's available time, according to the resource calendar, is being used to work on a particular task. Resources are the people, equipment, or other materials that are applied to completing a task.

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BUILDING THE PROJECT SCHEDULEAllocate resources to the tasks: The first step in building the project

schedule is to identify the resources required to perform each of the tasks required to complete the project.

A resource is any person, item, tool, or service that is needed by the project that is either scarce or has limited availability.

Many project managers use the terms “resource” and “person” interchangeably, but people are only one kind of resource.

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BUILDING THE PROJECT SCHEDULEIdentify the Interdependencies:

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WBS - DEFINITIONLogical breakdown of project into components and parts and is constructed by dividing project into major parts with each being divided into subparts.

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HOW DOES WBS HELP?

1.Effective planning by dividing the work into manageable elements which can be planned, budgeted and controlled

2. Assignment of responsibility for work element to project personnel and outside agencies

3. Development of control and information system

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WBS - GUIDELINES

1. Should reflect how the Project Manager plans to manage the project

2. Emphasis must be on meeting project objectives

3. The larger or more complex the project, the more levels in the WBS

4. If work is needed that requires effort or funding, it should be included in the WBS

5. It should reflect the total effort

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PRINCIPLES FOR CREATING WBS

The WBS must be mutually exclusive

The WBS must follow 100% rule

Know when its enough

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MUTUALLY EXCLUSIVE No overlap between two work packages

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THE 100% RULE The sum of all work packages must

include 100% of the scope of work Applies to all levels of WBS The sum of WBS element at lower level must

equal to 100% of parent level The WBS must not include any work that is

not included in the scope of work

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KNOW WHEN ITS ENOUGHStop when the package full fills these criteria :

1. You can create accurate estimate2. Only one type of resource is required per work

package3. There is no significant separation of time

between activities inside the work package 4. There is no activity mixed with other activity

inside work package that contains a risk that requires special attention

5. There is no need to create separate cost estimate for activities inside the work package

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A TYPICAL WORK BREAKDOWN STRUCTURE

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PROJECT MANAGEMENT TOOLS

PERT Chart- designed to analyze and represent the tasks involved in completing a given project

Gantt Chart - popular type of bar chart that illustrates a project schedule

BAR CHARTS/GANTT CHART Most projects, however complex, start

by being depicted on a bar chart. The principles are very simple:

Prepare list of project activitiesEstimate the time and resources neededRepresent each activity by a barPlot activities on a chart with horizontal

time scale showing start and end20

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GANTT CHART

ESTIMATING ACTIVITY TIME Time to complete a task is random:

Skill levels and knowledge of the individuals

Machine/equipment variationsMaterial availabilityUnexpected events

Illness Strikes Employee turnover and accidents Changed soil/site conditions

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ESTIMATING ACTIVITY TIME We know unexpected events and occurrences

will happen but are unable to predict the likelihood with any confidence

We must however account for the possibility of the occurrence of these events

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ESTIMATING ACTIVITY TIME Optimistic Completion Time - is the

time the activity will take if everything goes right

Pessimistic Completion Time - is the time the activity will take if everything that can go wrong does go wrong but the project is still completed

Most Likely Completion Time - is the time required under normal circumstances

It can also be the completion time that has occurred most frequently in similar circumstances

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ESTIMATING ACTIVITY TIME To compute the expected duration time the

following formula is used: E = (O+4M+P)/6 E = Expected duration time O = Optimistic time M = Most likely time P = Pessimistic time

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SEQUENCING ACTIVITIES Bar chart Produce a Logical Network Critical Path Method

Arrow DiagramsPrecedence Diagrams

Identify Critical Activities Locate the Critical Path Determine Floats

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PERT CHART

CPM: CRITICAL PATH METHOD Graphic network based scheduling

technique Arrow DiagramsPrecedence Diagrams

Use activities created by the WBS process

Analysis of timing and sequencing logicAids in identifying complex

interrelationship of activities 28

CPM: CRITICAL PATH METHOD Allows for easy revision of schedule and

simulation and evaluation of the impact of changes

Also used as a control tool during execution of the project

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STEPS IN PRODUCING A NETWORKS List the activities Produce a logical network of activities Assess the duration of each activity Produce a schedule - determine the start and

finish times and the float available for each activity

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STEPS IN PRODUCING A NETWORKS Determine the time required to complete a

project and the the longest path on the network The longest path is the Critical Path

Assess the resources required

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ACTIVITY SEQUENCING ACTIVITY IMMED.

TIME(WEEKS)PRED. (E)

A Set conference date - 2.0 B Establish theme/program - 5.0 C Select conference site A

5.0 D Obtain speakers B

6.0 E Develop brochure C,D 9.0 F Obtain mailing labels C,D 5.0 G Mail brochure E,F 2.0 H Obtain speaker materials D 4.0 I Receive registrations G 6.0 J Confirm all arrangements H,I 1.0 K Prepare conference kits J

2.0

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SAMPLE NETWORK

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start

b d

a c

f

e

g i

h

j k end

ACTIVITY TIMES/CRITICAL PATH

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Start

b5 d6

a 2 c

f5

e

g i

h4

j1 k2 End

0 2 2 7 11 20

5 9 20 22 22 28

2 6 28 29 29 31

4 6 6 11 11 20

20 22 22 2811 16

0 5 5 1111 15 28 29 29 31

0 5 5 1124 28

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CRITICAL PATH Calculations for precedence diagrams

and arrow diagrams are essentially the same

Critical path is where there is zero slack time

If an activity takes longer than estimated on the critical path then the project will be delayed

The critical path can change if there is a delay that make an alternative path longer 35

FLOAT (SLACK) Slack or float time is amount of delay

that could be tolerated in the start or completion time without causing a delay in completion of the project

Total float or calculations to determine how long each activity could be delayed without delaying the project

Total float = LF - ES - duration

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SUMMARY Critical path identifies the project time

requirements Slack or float time is amount of delay that

could be tolerated in the start or completion time without causing a delay in completion of the project

Zero slack time equals the critical path

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