Schedule approach used to approximate total project time duration.

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

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1. Critical path method (CPM)

Critical Path
Method It is a network connection
diagram approach used to approximate total project time duration. The
network diagram chart will have the vertex which having connection .used forward
pass and backward pass technique on the diagram .This tool will help us reduce project schedule overruns time . A
critical path for the projects is the series of activities (vertex) that
determine the earliest time by which the project can be done in time. There are tasks which was equivalent running on projects and most of projects have several paths through a network diagram chart.
The longest path is a critical tasks is what is driving the completion date for
the project. We are not finished with the project until we have finished all

For calculating the Critical Path for a
project, we must

Create a network diagram requires a activity
list which is based on project .After creating a network diagram chart, we must
also approximate the duration of each activity to determine the critical path.
Calculation of critical path involves adding the time durations taken by all
activities on each path through the network diagram. The longest path is 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

·
Makes dependencies visible between the project
activities

·
Increases visibility of impact of schedule revisions

·
Enables the Project Manager to optimize efficiency

·
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)

PERT 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.

·
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