Tips for Critical Path, Total Float & Free Float

I would like to start the topics which can bring more fruits with little scope of doubts. If a little attention is paid on these topics, there are very less chances of ambiguity. Yes, you have guessed it right, I will concentrate on the topics with numerical problems.

Today I will talk about the above topics in the subject of the post. Numerical problems are not lengthy and the calculations involved are very simple.

Critical Path - This is the longest duration path in the network diagram but the shortest possible time to complete the project. I am assuming here that you have already prepared the network diagrams and know its basic concepts. Once you have the network diagram ready, look at the each possible path from start to finish, calculate the duration of each path, the path with the longest duration is the critical path. It is possible to have more than one critical paths in a project. More the critical paths riskier the project.

Let's look at an example. Click on the below image to enlarge.





There are three paths -
1. Start-A-C-D-F-H-End = 11 days
2. Start-A-C-E-H-End = 8 days
3. Start-B-G-I-End = 12 days

Path 3 (Start-B-G-I-End) shown in Red is the critical path as this has the longest duration.

Path 1 (Start-A-C-D-F-H-End) is near critical path. A project manager not only should watch out for the critical path but also should concentrate upon the near critical path as this has the potential to become a critical path if not managed well.

Free Float - This is the time by which an activity can be delayed without delaying the early start of its successor activity.

Free float of an activity = (ES of the next activity - EF of that activity) - 1
(Note: -1 is there if you are considering the 1st day of the project as 1 but if you consider the 1st day of the project as 0th day, -1 will be omitted)

Total Float - This is the total time by which an activity can be delayed without delaying the scheduled end date of the project.

Total float of an activity = (LF - EF) of that activity OR (LS-ES) of that activity

Unless specifically asked for free float in questions consider float=total float.

Activities on the critical path have ZERO float.

In the above diagram,

Free Float for activity F = ES of H - EF of F - 1 = 11-10-1 = 0
Total Float for activity F = (LS - ES) of F OR (LF - EF) of F= 11-10 = 1

Free Float for activity E = ES of H - EF of E - 1 = 11-7-1 = 3
Total Float for activity E = (LS - ES) of E OR (LF - EF) of E = 11-7 = 4

More Sample Questions (PMBOK 4th Edition)

More sample questions. Answers and more links at the end of the post.

Q1 - Project manager acts as a coordinator or expediter in -

A. Weak matrix organization
B. Strong matrix organization
C. Projectized organization
D. Functional organization


Q2 - Due to change in the objectives of an organization the decision was taken to terminate a project. Which of the following project should be terminated -

A. Project where deliverables have been rejected by the client
B. Project where client is satisfied but it does not have a project charter
C. Project where two of the critical resources have left the organization
D. Project which has failed quality control checks


Q3 - You have joined the project mid-way as a project manager as the earlier project manager left the organization. To understand the project success criteria and the sign-off authority, you will look at -

A. Project Statement of Work
B. Project Scope Statement
C. Project Charter
D. Project Management Plan


Q4 - A new technology to develop a software has arrived in the market. As a project manager, you have a visibility into the client's roadmap and are aware that this technology will be used in your project. As a proactive measure, you have trained your resources in that technology. You have implemented -

A. Corrective Action
B. Defect Repair
C. Preventive Action
D. Organization training policy


Q5 - Your team is just about to implement the design when one of your team member approaches you with a new design for software development. This design will reduce the development time by half What is the FIRST thing you will do -

A. Implement the new design
B. Assess the impact of the new design on scope, cost & quality
C. Prepare a change request and take it to change control board
D. Refuse to make any change in the design now


Q6 - Requirements traceability matrix is an output of -

A. Collect Requirements
B. Define Scope
C. Create WBS
D. Control Scope


Q7 - Project scope statement, WBS & WBS disctionary constitute -

A. Schedule Baseline
B. Cost Baseline
C. Risk Baseline
D. Scope Baseline


Q8 - Which of the following BEST describes the purpose of Project Charter -

A. It identifies the stakeholders and their role on the project
B. It provides detailed scope of work
C. It authorizes the project manager to work on the project and apply resources
D. It lists all the risks associated with the project


Q9 - You are working in a construction company and are developing project scope statement for a new project. Which of the following is NOT part of Define Scope -

A. Project Charter
B. Product Analysis
C. Scope Verification
D. Alternatives Identification


Q10 - Which of the following is NOT an output of Close Project Phase -

A. Project Files
B. Final product
C. Project Closure documents
D. Project Statement of Work




















Answers
Q1 - A - PMBOK Guide 4th edition P29, Sec 2.4.2

Q2 - B - A project does not have any existence without project charter, hence this should be closed

Q3 - C - PMBOK Guide 4th edition P78, Sec 4.1.3.1

Q4 - C - PMBOK Guide 4th edition P92, Sec 4.4.3.1

Q5 - B - Before taking any change request to Change control board, always assess the impact of the change on scope, cost, schedule and quality.

Q6 - A - PMBOK Guide 4th edition P111, Sec 5.1.3.3

Q7 - D - PMBOK Guide 4th edition P122, Sec 5.3.3.3

Q8 - C - PMBOK Guide 4th edition P73, Sec 4.1

Q9 - C - PMBOK Guide 4th edition P112, Sec 5.2

Q10 - D - PMBOK Guide 4th edition P101, Sec 4.6.3

Here are the links for more practice questions -

1. 3500 Question Exam Simulation CD-ROM
2. 1000 PMP Exam Questions with Explanations, 5 Full Length Exams: Based on PMBOK 4th Edition

For more sample questions, visit:

1. PMBOK Guide 4th Edition Sample Questions
2. My PMP sample questions

Important Topics for PMP exam - Part 3

Delegation is one of the important topics and features regularly in PMP exam. I will try to throw some light on this topic today.

What is delegation?
This is a process of distributing the work (authority) to the individuals working on the project without getting away from the responsibility. When the work is delegated, it is expected that the person accepting the work is reliable and will be held accountable for the end results of the assignments. However, the final responsibility still lies with the project manager.

Delegation is not about dumping the work or passing the buck. It should be noted that when the work is being delegated the right authority to complete that work is also delegated but a control is maintained.

Why Delegate?
Vijay Verma, the author of "The Human Aspects of Project Management: Organizing Projects for Success" says -

"Effective delegation is essential in a project environment because of tight schedules and scarce resources. It is important to delegate work in order to increase effectiveness and efficiency in managing a project, reducing the crisis atmosphere. Delegated tasks provide stimulus and opportunities to project team members, improving their participation and interest in the project and possibly opening new horizons for them. In addition, delegation creates more free time for the project manager to work on the most important and critical tasks, as well as, simply, more time to think. Creative thinking by the project manager and interested, challenged project team members helps to avoid the "one-person band" syndrome."

The different aspects to consider while delegating are - to motivate the team, to boost up their morale, to provide them with the challenges, to create successors. Delegation is not about relieving your workload but to allow employees grow professionally. Effective delegation is used to benefit both yourself and the team you are working with.

Following points should be kept in mind while delegating -

1. What should be delegated - Not every task a project manager does should be (can be) delegated. Project manager must evaluate the risks before delegating the tasks. The manager should delegate the tasks to free up his time to concentrate on priority activities - routines tasks can be delegated, technical tasks requiring expertise can be delegated, future roadmap planning should not be delegated, key team member selection should not be delegated.
   
2. Clarity of the results - As a manager you must establish the end results out of those tasks. The means to achieve the end results should be left for the individual to decide. Emphasize the goals not the processes or procedures. If for some reason, specific method has to be adopted, it should be informed right at the start of the assignment.
   
3. Defining the responsibility - You as a manager should determine employee's level of responsibility and ensure employee understands this as well.
   
4. Delegating the authority - Major failures in task delegation happens due to lack of authority delegation. Task delegation is done but authority delegation does not happen. Hence, for every small decision employee runs to the supervisor for the approval. Authority required for successful accomplishments of the tasks should also be delegated.
   
5. Establishing the timelines - A clear and agreed upon timeline must be published and milestones should be monitored in project progress reviews.
6. Support & feedback - It encourages the employee taking up the tasks if timely feedback is provided alongwith the continuous support. If required, training should also be provided to achieve the set goals.

For further reading, please refer to "The Human Aspects of Project Management: Organizing Projects for Success" by Vijay Verma (to read this requires PMI membership). Others can buy this book here.

Also visit:
Important Topics for PMP exam - Part 1
Important Topics for PMP exam - Part 2