critical path method
Critical Path : is a combination of activities that, if any are delayed, will delay the project’s finish date.
Purpose of critical path method:
1. To calculate the project’s finish date.
2. To identify how much individual activities in schedule can slip with delaying project
3. To identify the activities with the highest risk that cannot slip without changing the project finish date.
Float Calculation using CPM
● Float is the amount of time an activity can be delayed without delaying the project end date.
● Float is always Zero on Critical Path activities.
● Critical Path is longest path of network diagram.
Each activity have same box
ES : Early Start
EF : Early Finish
LS: Late Start
LF : Late Finish
Float = LS-ES or LF-EF
Float Calculation
Late Start(LS) – Early Start(ES)
OR
Late Finish(LF) – Early Finish (EF)
Example
You are the project manager of project at SkillsMag and following activities are identified along with the activity effort.
Project A | ||
Activity | Preceding Activity | Duration (Wks) |
Start | None | 0 |
A | Start | 1 |
B | Start | 3 |
C | Start | 5 |
D | A | 9 |
E | B,C | 2 |
F | C | 3 |
G | D | 4 |
H | E | 8 |
I | F | 2 |
End | G,H,I | 0 |
First prepare schedule network Diagram
network diagram
Step 2:
Calculate the ES and EF of each activity using forward pass technique.
Remember the following formulas for calculation.
Early Start (ES) = Early Finish(EF) of Predecessor activity. If no predecessor activity exists then 0.
Early Finish (EF) = Early Start (ES) + Activity Duration
Activity E is highlighted as it has 2 predecessor activities. we take higher one.
network diagram
Step 3:
Under this technique, we will start calculating the value from last activities on the path i.e. from G,H and I.
Thumb Rule : Take highest EF.
Our case we have EF 15 is highest for activity H.
The formula for LS(Late start) is
Late Start (LS) = Late Finish – Activity Duration
Activity c has 2 successor activity,take lowest one.
network diagram
Step 4 : Float calculation
float
Project integration management
Project Integration management is main responsibility of project manager. Here project manager has to do high level of project work and balancing between different processes.
[box] As per PMBOK®“Project Integration management includes the process and activities need to be identify, define, combine, unify and coordinate the various process and project management activities within the project management process groups.”[/box]
Figure given Below shows project integration management processes and their respective process groups
Project integration management | Process group (done during ) |
Develop project charter | Initiating |
Develop project management plan | Planning |
Direct &manage project work | Executing |
Monitor & control project work | Monitoring and controlling |
Perform integration change control | Monitoring and controlling |
Close project or phase | Closing |
Let’s have better understanding for each process of integration management.
Develop Project Charter:
This is very first part of integration management.
Develop Project Charter |
Inputs
1. Project Statement of work 2. Business case 3. Agreements 4. Enterprise environmental factors 5. Organizational process assets |
Tool and Techniques
1. Expert judgement 2. facilitation techniques |
Outputs
1. Project charter
|
[box]As per PMBOK®
“Develop project Charter is the process of developing a document that formally authorize a project or a phase and documenting initial requirement that satisfy the stakeholder need and expectation. ”[/box]
Project charter should be developed by project sponsor, Customer, PMO or they can delegate duty to Project manager.
Project Manager is assigned in this process.
It formally authorizes the project.
Now let’s have a look on input, tool & technique and outputs of project charter
Inputs
Project statement of work:
[box]As per PMBOK®“The statement of work (SOW) is a narrative description of product or a services to be delivered by project.” [/box]
The project statement of work contains
Business case:
Business case provides necessary information from business point of view whether project is feasible or not.
Business case is created based on one of following points
Agreements:
When working for external customer the contract is used as an input.
Enterprise environmental factors:
Enterprise environmental factors that can affect the development of project charter.That can be
Organization Process assets:
The organizational process assets that can effect development of project charter process may contain Organization standard process, Templates, Historical information and lesson learned and knowledge base.
Tool & Techniques
Expert judgement technique is used in every integration management process.
In this judgement is provided based on expertise by expert person of their fields.
They can be individuals, subject matter expert (SME), Consultant, stakeholder or group(s).
Brainstorming, managing meetings and keeping them on track, resolving conflict, and resolving problems are part of facilitation techniques. These techniques are used by facilitator.
Outputs
Project Charter is final outcome of develop project process. It provides summary of project.
Project Charter contains following things
Project management plan is master plan for project. It is developed once project charter is approved.
[box] “Develop project management plan is process of documenting the actions necessary to define, prepare, integrate and coordinate all subsidiary plans. The project management plan define how the project is executed, monitored & controlled and closed.”[/box]It integrates all the knowledge area. It also include baseline of project. Project baseline once defined can only be change through perform integrated change control process.
To develop successful project plan one should have following skills.
Develop project Management plan |
Inputs
· Project Charter · Output from planning process · Enterprise environment factor · Organizational process assets |
Tool & Techniques
· Expert judgement · Facilitation techniques |
Output
· Project Management plan |
Inputs
Project Charter: Please click here to see more about project charter.
Output from planning process:
Information from other planning processes help to develop project plan.
Table below shows various planning process
Scope management plan |
Requirement management plan |
Project scope statement |
Scope baseline |
Schedule management plan |
Schedule baseline |
Cost management plan |
Cost performance baseline |
Quality management plan |
Process improvement plan |
Human resource plan |
Communication management plan |
Risk management plan |
Procurement management plan |
Stakeholder management plan |
Enterprise environment factors: Please click here to see more about Enterprise environment factors.
Organizational process assets: Please click here to see more about Organizational process assets.
Tools and Technique:
Expert judgement
Expert judgement technique is used in every integration management process. In this judgement provided based on expertise by expert person of their fields. They can be individuals, subject matter expert (SME), Consultant, stakeholder or group(s).
Facilitation techniques
Brainstorming, managing meetings and keeping them on track, resolving conflict, and resolving problems are part of facilitation techniques. These techniques are used by facilitator.
Output:
Project management plan is main output of this process. It is a formal approved document. Table above shows components of that.