Schedule Development

Numerous projects was unsuccessful

to meet schedule prediction

because of lack of schedule development to overcome

this. There are methods which used for project schedule. Such as critical path method and PERT method

1. Critical path method (CPM)

This

is the method which is used calculate the time duration which is taken by

project. The critical path method help to estimate the time which used to

schedule development. Critical method used by many organization to estimate the

time duration because in a single project there are multiple tasks running simultaneously

CPM able to show which task take how much time to complete . there are two way

to calculate CPM forward pass and backward pass .Which help to estimate earliest

time for the project the longest path is consider as Critical path . Because it

included all Critical element.

The

Critical path method is network diagram which have nodes in it .Every node have

task and value assigning to it by find the relationship between the node and after

calculating the node value we come to know the Critical path

For example:

The critical path is the chain of activities with

the longest time taken duration. A slow up in

any of these activities will result in a delay for the whole project. This critical path example help us to

understand the how this method work.

Using the Critical Path Method (CPM)

The

duration of each activity is listed above each node in the diagram. For each

path, add the duration of each node to determine it’s total duration. The

critical path is the one with the longest duration.

There

are three paths through this project.

Start

-> Activity1->Activity3->Activity4->finish 3+7+2=12

Start

-> Activity2->Activity3->Activity4->finish 5+7+2=14 (Critical Path)

Start

-> Activity2->Activity5-> finish 5+4=9

Advantages of CPM

·

Makes dependencies visible between the project

activities

·

Increases visibility of impact of schedule revisions

·

Enables the Project Manager to optimize efficiency

Disadvantages of CPM

·

For large and complex projects, there’ll be thousands of

activities and dependency relationship

·

The Critical Path Method does not account

for resource and resource allocation

2. Program Evaluation and Review Technique (PERT)

Second method is PERT .It was initially used

by defiance in their Polaris project .In this method the activities time

duration is found.

By using these following formula:

Duration =

And,

Standard Deviation =

This network analysis is a method used to approximate

project time duration when there is a unpredictability

occurs in the individual activity time duration approximates. PERT applies the

critical path method (CPM) to a weighted average time duration approximate.

This approach was developed about the same time as CPM, in the late 1950s, and

also uses network diagrams concept, which are still sometimes referred to as

PERT charts. PERT uses probabilistic time approximates duration. Approximation

based on using optimistic time, most likely time and pessimistic time approximates

of activity durations instead of one specific or discrete duration approximate,

as CPM does .By using the PERT weighted average for each activity duration approximate,

the total project duration approximate takes into account the risk or

uncertainty in the individual activity estimate.

For example:

Suppose a project team in the project case

used PERT to determine the schedule for the online application registration

system project. They would have to collect data for the optimistic, most

likely, and pessimistic duration approximates for each project activity. Suppose

one of the activities was to design an input screen for the system. Someone

might approximate that it would take about two weeks or 10 workdays to do this

activity. Without using PERT, the duration approximate for that activity would

be 10 workdays. Using PERT, the project team would also need to approximate the

pessimistic and optimistic times for completing this activity. Suppose an

optimistic approximate is that the input screen can be designed in eight workdays,

and a pessimistic time approximate is 24 workdays.

Applying the PERT formula:

PERT weighted average =

= 12

Instead of using the most likely duration approximate

of 10 workdays, the project team would use 12 workdays .These additional two

days could really help the project team in getting the work completed on time.

Advantage of PERT

·

A PERT chart makes planning

large projects easier

·

PERT is a way of making

relationships visible in a diagram

·

PERT makes the critical path

visible

Disadvantage of PERT

·

PERT charts can be

complicated and confusing, with hundreds or even thousands of tasks and

dependency relationships

·

PERT diagrams can be expensive

to develop, update and maintain.

·

PERT charts depend on the

ability to predict precise time frames for multitudes of tasks