Critical Path Method:

It is the method of keeping a check on activities in our project which has potential of delaying our project completion dates.

The critical path methods actually consist of two methods CPM-1 and CPM-2.

In CPM-1 each operation of a project is considered to be performed in only one way. In CPM-2 alternate methods are considered for performing some or all of the operations of the project.

Here only CPM-1 will be considered.

CPM-1:

CPM-1 divides the management function into two distinct phases

Ø      Planning

Ø      Scheduling

Planning is deciding of what should be done whereas Scheduling is the determining of when operations should be done. With this separation of function it is possible to determine what operations actually control significant completion dates.

CPM-1 has several levels of application. One listing of these applications is the following:

Ø      Describe project in terms of dependencies among operations i.e. plan the project

Ø      Determine schedule of operations.

Ø      Determine those operations that control significant target dates of the project.

Ø     Analyze schedule

Ø      Replan project if analysis is indicates.

Ø      Allocate resources to project in an efficient manner for the schedule development.

Arrow diagram:

The critical path method is a graphical process which management can use as an aid in planning a scheduling operation in a project. In other words CPM-1 is a graph of operations.

Relationships among operations:

Every operation in project is related to the other operations in a project in one or more than one way:

Ø      It must precede some operation.

Ø     It must follow some operations.

Ø      It can be done at the same time other operations are being performed.

Arrow network:

Of course the whole project consist of many operations and the CPM-1 graph for the project is called arrow network. Arrow network is constructed on the operation-by-operation bases. Which shows following relationships:

Ø      What operations must immediately precede this operation?

Ø      What operation cannot be started until after completion of this operation?

Ø      What operation can be done concurrently with this operation?

Associated with each arrow in the network in a time length called the duration of that activity. The activity starts at the tail of the arrow and it end at the tip of the arrow.

Project completion time-(E.S.T Schedule):

Nodes are the events or the points in time that are provided at the start and end of the each arrow activity or arrow network.

It is the usual practice that we provide (0) at the first node of the arrow diagram.

Earliest Possible Start- (EPO):

It is the earliest possible time for which any activity or a project can be started.

Latest Possible Start – (LPO):

It is the latest possible date or time at which any activity or project can be stated with profit.

Free Float:

In the most simplest way it can be defined as time between two activities with which the predecessor activity can be delayed with out effecting the early start of its successor activity is called free float.

Total Float:

It is time that can be provided in between all the activities of the project, with which the completion dates of the operation cannot be effected.

Critical Activity:

The activity that had a potential of delaying our project or have zero float.  

Critical Path:

It is the longest path of activities of zero floats.

It should be noted that only those activities control the completion dates of the project that has float or some margin of time. And all the activities in a project that do not have any kind of float do not control the completion dates of the project.

  Break Down:

Process of break down is a way by which we can break down our project into different phase and responsibilities etc. By which we can strictly monitor our project progress and critical actives and their progression. In more advanced terms it is called work break down structure.