Objective Of Project planning

Feasibility StudyResource AllocationDetailed CostingMotivationCo-Ordination

When to Plan Planning is an ongoing process of

refinement. Each iteration becoming more detailed and

more accurate than the last. During the feasibility study and project start

up, the main purpose of planning will be to estimate timescale and the risk of not achieving target completion dates or keeping within budget.

When to Plan As the project proceeded, the emphasis will

be placed upon the production of activity plans for ensuring resource availability and cash flow control.

Project Schedules

Now the project is developed to the level of showing dates when each activity should start and finish and when and how much of each resource will be required.

Steps for creating Project schedule The first step is to decide what activities need

to be carried out and in which order they are to be done

With the help of this we can construct an ideal activity plan.

i.e. a plan of when each activity would ideally be undertaken were resources not a constraint.

This activity plan is generated by step 4 and 5.

Steps for creating Project schedule contd… In second step, the ideal activity plan will

then be subject of an activity risk analysis, aimed at identifying potential problem.

This might be the alternative of idea activity plan.

Steps for creating Project schedule contd… The third step is resource allocation. The expected availability of resources might

place constraints on when certain activities can be carried out and ideal plan might need to be adapted to take into account of this.

Steps for creating Project schedule contd… Final step is schedule production. Once resource have been allocated to each

activity, we will be in a position to draw up an publish a project schedule.

Which indicates planned start and completion dates and a resource requirements for each activity.

Project and Activity Defining activity Identifying activity

Process based activity Product based activity Hybrid approach

A WBS based on deliverables.

Network Planning Models Project scheduling techniques model the

project’s activities and their relationships as a network.

In the network time flows from left to right. In 1950s these techniques were developed. These techniques are:

CPM Critical Path Method PERT Program evaluation review techniques

Formulating a Network Model The first stage in creating a network model

is to represent the activities and their interrelationships as a graph.

In CPM we do this by representing activates as links (arrowed lines) in the graph

And nodes (circles) representing the events of activities starting and finishing.

For Example

CPM networks are examples of directed graph. Here are some rules for constructing CPM.

A project network may have only one start node.A Project Network may have only one end node.A link has duration. (Link represents the activity

and activities take time to execute)Nodes have no duration. (Nodes are events and

are instantaneous points in time. Source node is the event of the project becoming ready to start. And sink node is the event of the project becoming completed)

Constructing CPM Networks

Figure represents node 3 is the event that both coding and data take on have been completed and activity program testing is free to start.

Installation may be started only when event 4 has been achieved i.e. as soon as program testing has been completed.

Constructing CPM Networks

Next step is Time moves from left to rightNodes are numbers sequentiallyA network may not contain loops.(If loop exist

then it is an error that represents a situation that can not occur in practice.)

Like below figure shows the logic that suggests that program testing cannot start until the error has been corrected.

Constructing CPM Networks

A network may not contain dangles (As shown in figure that write user manual cannot exist as it would suggest there are two completion points for the project.)

Precedents are the immediate preceding activities.

Constructing CPM Networks

What is wrong with figures and where possible redrawn them correctly

When two paths within a network have a common event although they are in other respects independent a logical error might occur

Using Dummy activates

We can resolve this problem by separating the two independent paths and introducing a dummy activity to link completion of DS design to start of the activity placing an order.

Dummy activities have a zero duration and use no resources which is shown as dotted lines.

Using Dummy activates

Example of Dummy activates

Where parallel activities have a time lag we may show this as a ladder of activities. In this case documentation may proceed alongside prototype testing so long as it starts at least a day later. It will finish two days after the completion of prototype testing.

Representing Lagged activates

Now we are ready to start thinking about when each activity should be undertaken

The Critical Path method is concerned with 2 primary objectives:Planning the project in such a way that it is

completed as quickly as possibleAnd identifying those activities where a

delay in their execution is likely to affect the overall end date of the project or later activities’ start dates.

Adding Time Dimension

The method requires that for each activity we have an estimate of its duration

We have two passes to analyse the network:Forward Pass: which is use to calculate the

earliest dates at which activities may commence and the project be completed.

A Backward Pass: which is use to calculate the latest start dates for activities and the critical paths.

Contd..

Critical path method is a network analysis technique used to predict the project duration by finding out which sequence of activities (Critical Path) has least amount of scheduling activity.

In this technique: Project manager identifies the critical activities of the project that constitute the critical path of the project.

CPM

Specify the individual activities (With the help of WBS)

Determining the sequence of those activates (finding the immediate predecessors)

Draw a Network Diagram (by the sequencing of activities)

Estimate the completion time for each activity (Based on past experience)

Identify the Critical PathUpdate the CPM diagram as project

progresses.

Steps in CPM technique

The Critical Path is the longest duration path through the network where no activity is slack.

The amount of time in which a non critical path activity can be delayed without delaying the project is known as slack time.

Critical path can be identified by following 4 parameters:Earliest Start DateEarliest Finish DateLatest Finish DateLatest Start Date

Critical Path

Typically the diagram is used to record information about the events rather than the activities.

CPM network Conventions

Draw an activity network diagram using CPM conventional for the project specified in table.

Example

The CPM network for the example project...

Example Contd..

The forward pass is carried out to calculate the earliest date on which each event may be achieved and the earliest date on which each activity may be started and completed.

The earliest date for an event is the earliest date by which all activities upon which it depends can be completed.

Forward Pass

Forward Pass

Forward Pass

Forward Pass

Forward pass rule: the earliest date for an event is the earliest finish date for all the activities terminating at that event. Where more than one activity terminated at a common event we take the latest of the earliest finish dates for those activates.

Table after forward pass

Backward PassA backward pass is use to calculate the latest

date at which each event may be achieved, and each activity started and finished, without delaying the end date of the project.

The latest date for an event is the latest date by which all immediately following activities must be started for the project to be completed on time.

To calculate to latest dates, we assume that the latest finish date for the project is the same as the earliest finish date i.e. We wish to complete the project as early as possible.

Backward Pass

Backward PassThe latest date for node 6 is assumed to be

week 13, the same as the earliest dat.The latest date for event 5 is week 10, since

activity G will take 3 weeks and must be completed by week 13 if the project end date is not to be exceeded.

The latest date for event 4 is week 11 since activity H does not need to be started until week 11 if it takes 2 weeks and does not need to be completed until week 13.

Backward PassThe latest date for event 3 is the latest date by

which we must be in a position to start both activities D and E. Activity E need not finish until week 10 and need not therefore start until week 7. activities D need finish until week 11 and, having a duration of 4 weeks, need not start until week 7. the latest date for event 3 is therefore week 7.

The latest date for event 2 is week 8 since C, which takes 3 weeks, need not be finished until week 11

The earliest and latest dates for the start event must always be the same unless an arithmetic error has occurred.

Backward PassThe latest date for event 1 is the latest by

which we must be in a position to start activity A (Which must start by week 2), activity B (which must start by week 3) and activity F (which must start by week 0). This event’s latest date is therefore zero. This is not very surprising since it tells us that if the project does not start on time it wont finish on time.

Total FloatWhereas events have slack, activities posses float. Total float is the difference between the earliest

start date of an activity and its latest start.It shows that how long the activity’s start or

completion may be delayed without affecting the end date of the project.

Total Float

Advantages of CPMIt provides a realistic and disciplined basis for

determining how to attain these objectives.They are useful in new project’s management.It shows dependencies to help scheduling.It demines slack times.It evaluates which activities can run parallel

to each other.The activities and their outcomes can be

shown as a network.It determines the project duration which

optimizes both direct and indirect costs.

Disadvantages of CPMCPM networks can be too complex.It does not handle the scheduling of

personnel and the recourse allocation.The critical path is not clear and needs to be

calculated carefully.Estimating the completion time of an activity

can be difficult.

Similarities between PERT & CPMBoth are use Network Diagrams.Both are used to plan the schedule of individual

activities.Both can be used to determine the

earliest/latest start and finish times for each activity.

Both have single “Start” and “Finish” Activity.Both determines the critical path in entire

network.

Differences between PERT & CPMIt basically deals with

time estimateIt is probabilisticIt takes into

consideration three time estimates.

Estimates are uncertain.

Estimation are based on past experiences, most likely and not accurate timing

It deals with both time and cost

It is deterministicIt is based on single

time estimateOnly one number is

used for an activity’s time estimate.

Estimates of activity are based on historical data.