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Project Expeditor vs Project Coordinator for PMP Exam – Updated PMP, PMI-ACP & ITIL Exam Tips 2020

Project Expeditor and Project Coordinator

In Weak Matrix organizations, there are usually no “real” project managers; even if there is a post of “Project Manager”, they usually perform the role more of a Project Coordinator or Project Expeditor. For strong matrix and projectized organizations, Project Expeditor and Project Coordinator may exist alongside with the Project Manager.

  • Project Expeditor: A Project Expeditor usually carries the responsibility of staff assistant / communication coordinator.
    • A Project Expeditor is not given the authority (or very low authority) to make or enforce decisions.
    • The Project Expeditor will communicate with various parties of the project to ensure timely action.
    • For larger projects, the Project Manager may have some Project Expeditors assisting them for communication and logistics.
  • Project Coordinator: A Project Coordinator carries the responsibility of partially managing the project under the supervision of other managers.
    • A Project Coordinator is usually given some sort of limited authority to make decision.
    • For larger projects, the Project Manager may have some Project Coordinators reporting to them.

The power or authority of the roles of Project Manager, Project Expeditor and Project Coordinator is listed in descending order:

  1. Project Manager
  2. Project Coordinator
  3. Project Expeditor

Mock Exam Question

  1. Kylie is working on a project as a project management team member. Her duties involves updating the information of the project progress, communicating with stakeholders for updates and responding to enquiries when the project manager is away. She is given limited authority to make decisions based on the project manager’s instruction. Which of the following title best describes Kylie?
    1. Junior Project Manager
    2. Project Expeditor
    3. Project Staff
    4. Project Coordinator

Solution: D
Project Coordinators’ duties include helping the project manager for day-to-day work as well as making decision for certain issues with authority pre-approved by the project manager. Therefore, Kylie should be working as a project coordinator for the project described above.

Source: Project Expeditor vs Project Coordinator for PMP Exam – Updated PMP, PMI-ACP & ITIL Exam Tips 2020

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Project Benefit Analysis Concepts for the PMP Exam (Part 2) – Updated PMP, PMI-ACP & ITIL Exam Tips 2020

Net Present Value (NPV)

Net Present Value (NPV) of the sum of all cash inflows (in Present Value) of the project minus the initial cost, i.e.  PV (benefits) – PV (costs)

The formula for Net Present Value formula is:

Net Present Value (NPV) = Σ(Pi / (1+ r) n) – Ci

where Pi is cash inflow; r is interest rate; n is time periods; Ci is initial cost.

Let’s introduce the concept of Present Value (PV) first. Since there are inflation/deflation, $1000 now does not have the same purchasing power as $1000 in four years (i.e. owing to inflation, you can buy less with $1000 four years later). In order to adjust for inflation/deflation, Present Value (PV) is introduced. Present Value (PV) is the future value in terms of today’s money with adjustment for inflation. This would provide an accurate figure to be used in benefit comparison.

Don’t worry, for the PMP® Exam, candidates are not required to calculate the present value or net present value. You will only need to know that:

  • NPV is an effective tool to help determining whether a project will be profitable or not;
    • NPV > 0 — the project is profitable
    • NPV = 0 — the project will break even
    • NPV < 0 — the project will lose money

The following would be a mock exam question on net present value:

  1. For the facility expansion project, $100,000 would be needed which is expected to generate a total of $200,000 (in present value) over 5 years. What is the Net Present Value (NPV) of the project?
    A. $100,000
    B. $200,000
    C. $300,000
    D. -$100,000
Solution: A
Since the Net Present Value (NPV) is the present value of all benefits minus all costs, i.e. NPV = $200,000 – $100,000 = $100,000.

Generally speaking,

The larger the Net Present Value (NPV), the more profitable the project is to the organization.

Benefit-Cost Ratio (BCR)

Benefit-Cost ratio is the ratio of the benefits of a project as compared to the costs calculated in terms of Present Value (PV).

As pointed out in the Net Present Value (NPV) section, the use of PV will allow the figures to be calculated more accurately with adjustments for inflation.

using the Net Present Value in calculating the BCR is inflation.

The formula for calculating Benefit-Cost Ratio (BCR) is:

Benefit-Cost Ratio (BCR) = Benefits (in terms of PV) / Costs (in terms of PV)

where benefits are the total value/revenue generated (without consideration for costs). Interpretation of Benefit-Cost Ratio (BCR) :

  • BCR > 1 — the project is profitable, and the higher the BCR the better
  • BCR = 1 — the project will break even
  • BCR < 1 — the project will cause the organization to lose money and is generally considered as not a good investment

The following would be a sample exam question on benefit-cost ratio:

  1. You are considering a project for the expansion of facilities to increase production owing to rising demands. The cost for the expansion work and equipment would be $1,000,000 (NPV). It is expected that an increase in revenue of $2,000,000 (NPV) would be realized with the expansion. What is the Benefit-Cost Ratio (BCR) of the project?
    A. 0.5
    B. 20
    C. 2
    D. Not enough information to calculation
Solution: C
Benefits = $2,000,000 and Costs = $1,000,000. Since BCR = Benefits / Costs = $2,000,000 / $1,000,000 = 2. NOTE: in the PMP® Exam, you will NOT be required to calculate the BCR.

Generally speaking,

The larger the Benefit-Cost Ratio (BCR), the more favourable the project is financially to the organization.

Internal rate of return (IRR)

Internal rate of return (IRR) is the interest rate at which the cash inflow and cash outflow of the project equals zero.

And the formula for Internal rate of return (IRR) is:

0 = F0 + F1/(1+IRR) + F2/(1+IRR)2+ F3/(1+IRR)3+ . . . +Fn/(1+IRR)n

where N is number of periods; F is cash flow.

The formula looks sooooooooooooo difficult. The good news here is that you will NOT be asked to calculate the internal rate of return (IRR) in the PMP® Exam. The only thing you need to know about Internal Rate of Return is that, the higher the IRR, the better.

The following would be a mock exam question on internal rate of return:

  1. There are three projects for the organization to choose from: Project A has an internal rate of return of 10%, Project B 20% while Project B -20%. Based on the information provided, which is the best project?
    A. Project A
    B. Project B
    C. Project D
    D. Not enough information provided
Solution: B
Project B has the largest internal rate of return, therefore it is deemed most profitable.

Generally speaking,

The larger the Internal Rate of Return (IRR), the more favourable the project is financially to the organization.


Depreciation is the decrease in value of assets over time.

The decrease in value can be attributed to many factors, take production machines as an example, the depreciation may be due to loss of efficiency, becoming out of date, new model coming out, etc.

There are three type of depreciation calculation techniques:

  • Straight Line Depreciation — the same amount is reduced in value over each year (the simplest depreciation calculation method).
  • Double-declining Balance — (accelerated depreciation) reduction in value is higher at first and lower later on (twice that for straight line depreciation in the first year with 40% less than the previous year later on).
  • Sum of Year Depreciation — (accelerated depreciation) greater depreciation in the earlier years of an asset’s useful life and less in the later years (e.g. for a machine with 5 years of service life, the sum of digit years =  1 + 2 + 3 + 4 + 5 = 15 and the depreciation for the first year is 5 / 15, the second year is 4 / 15 and so on).

Remember this,

Assets for a project will reduce in its value over time (depreciation).

Sunk Cost

Sunk Cost is the cost that has already been spent which cannot be recovered.

The emphasis here is sunk cost is not recoverable. For example, if the organization has spent $100,000 on installation of a software on all workstations in preparation for an expected change in technology, the $100,000 spent is the sunk cost. This cost cannot be recovered even though the organization later changed its mind to use another software package.

For the PMP® Exam, candidates should understand that sunk cost should NOT influence future decisions.

Take the software installation example further, suppose a new software package has come to market which is much much more suited to the organization needs, the management should decide whether to continue with the staff training and documentation ($100,000) of the originally installed software package or opted for the new software ($200,000 including training and documentation). The decision should now be made based solely on which software package is the best for the current moment and disregard the $100,000 spent on the original software package (i.e. the sunk cost).

In addition to sunk cost, there are also other costs which may appear in the exam:

  • Fixed Cost — take the software installation as an example, the fixed cost would be the monthly maintenance fee for buy fixes and upgrades
  • Variable Cost — that would be the electricity bill used to power the workstations as this would be different each month depending on actual usage
  • Direct Costs — expenses that are billed to the project directly, e.g. wages, material cost, etc.
  • Indirect Costs — costs that are shared among several projects, e.g. taxes, fringe benefits, PMO, etc.

The following would be a mock exam question on sunk cost:

  1. In a project, the organization has purchases a machine for $100,000 which was later found to be not suitable. What is the $100,000 termed as?
    A. Fixed Cost
    B. Sunk Cost
    C. Indirect Cost
    D. Opportunity Cost
Solution: B
The $100,000 has already been spent which is not recoverable, so it is sunk cost. Note: The cost can also be termed as “direct cost” as the machine is purchased with the sole purpose for the project, but this is not one of the choices for the question.


Do not let sunk costs to affect decisions as sunk costs are costs that are not recoverable. Focus on choosing the most feasible and beneficial action as the next step.

Payback Period

Payback Period is the time it takes for the organization to earn back the initial investment (in terms of monetary cost) to the project and begin making profits.

If the income generated from the project is constant, the payback period can be calculated using the simplified formula:

Payback Period = Initial Investment / Periodic Cash-flow

For example, if the organization need to invest US$10,000 into a project that is expected to generate US$1,000 per month, the payback period would be:

Payback Period = US$10,000 / US$1,000/month = 10 months

In the actual exam, candidates are seldom required to calculate the payback period for projects (after all, the exam is not an accounting exam). The exam inclines more on testing Aspirants’ conceptual knowledge, i.e. whether the candidate understands the meaning behind payback period or other terms.

The following would be a sample PMP® Exam question on payback period:

  1. You are the project manager of the organization and you are tasked with the responsibility of selecting a project from two proposals A and B based on the business values with the information on hand: Project A has a payback period of 20 months while Project B has a payback period of 30 months. Which one should you recommend?
    A. Project A
    B. Project B
    C. Neither one is beneficial to the organization.
    D. Ask the project sponsor to choose.
Solution: A
Based on the fact that only the payback period is provided, we should rely solely on this information to make the selection. Since Project A has a shorter payback period, it is considered financially more beneficial for the organization. NOTE: since you are tasked with the responsibility, it is not appropriate for you to escalate the decision making back to the project sponsor. Project Managers are expected to should responsibilities according to PMI, though in reality it is always the senior management / project sponsor to make the project selection.


Generally speaking,

The shorter the Payback Period, the more favourable the project financially to the organization.

However, Project Managers should note that Payback Period is rarely used solely as a project selection criterion. The organization would need to consider an array of different metrics in order to selection the projec with the best value realization to the organization. common project selection criteria include:

  • Return on Investment
  • Cost-benefit Ratio
  • Net Present Value , etc.

Return on Investment (ROI)

Return on investment (ROI) is the benefit an investment bring about, by comparing profits in relation to capital invested.

The formula for calculating Return on Investment for a project is (note that the PMP® Exam does not require candidates to calculate ROI):

Return on Investment = Net profit / Capital Invested

Net profit (usually expressed as net present value [NPV]) is the total capital invested minus all expenditure. If ROI is larger than 1, the project is deemed to be profitable. If ROI is smaller than 1, the project loses money.

A sample PMP® Exam question on return on investment:

  1. The organization is considering several projects with the following return on investment:
    ROI of Project A = 1.1
    ROI of Project B = 0.4
    ROI of Project C = 1.8
    ROI of Project D = 1.0
    By judging on ROI alone, which project is the most favourable choice?
    A. Project A
    B. Project B
    C. Project C
    D. Project D
Solution: C
Project C has the largest ROI. If ROI is the only metric to compare, Project C would be the best project to undertake.


Aspirants would only need to remember that:

The higher the Return on Investment, the more favourable the project financially to the organization.

However, in reality, ROI is not only project selection criteria. Let’s look at the mock question above again, if we further know that Project C is such a small project that the net gain from the project is US$8 while that for Project A is US$800,000. If you are the senior management, how will you choose again? It is really difficult to tell. Other factors must be considered.

But one thing is clear is that in the exam, the questions are usually simplified enough to ask you to make the choice based on a single metric which is never the case in real life situations.

Opportunity Cost

Opportunity Cost is the value of the best alternative given up when a choice is made, in which the choices must be mutually exclusive owing to limited resources.

In simpler terms, opportunity cost is the highest value a person needs to give up for the chosen choice. For example, if you have US$10, you can either buy a coffee or 2 muffins. When you purchased the coffee, your opportunity cost is 2 muffins as you don’t have the money to purchase the muffins.

For the PMP® Exam, Aspirants should only need to know that owing to limited resources (money, human, space, etc.), the organization will often need to select one project over the others. The Opportunity Cost is the single best alternative NOT chosen(NOTE: Opportunity Cost is not the sum of the values of all project given up). For most cases, the chosen project is believed to deliver the best values among all the project choices.

There is no calculation required for getting the opportunity cost.

A mock exam question on opportunity cost:

  1. You are the working in the PMO of your organization and there are three project proposals submitted. However, owing to the limitation of capital, only one project can be chosen. Project A would have a NPV of US$100,000, Project B would have a NPV of US$120,000 while Project C would have a NPV of US$50,000. What is the opportunity cost of choosing the project with the highest NPV?
    A. US$120,000
    B. US$50,000
    C. US$100,000
    D. US$150,000
Solution: C
Project B has the highest NPV and hence it is chosen. Based on the definition of opportunity cost, the second best NPV would be the best value given up. So the NPV of Project A would be the opportunity cost, i.e. US$100,000.

Project Benefit Analysis Concepts for the PMP Exam (Part 2)

Source: Project Benefit Analysis Concepts for the PMP Exam (Part 2) – Updated PMP, PMI-ACP & ITIL Exam Tips 2020

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Difference Between PERT and CPM (with Comparison Chart) – Key Differences

Eleven important differences betweeb PERT and CPM are discussed in this article. One such difference is PERT is a technique of planning and control of time. Unlike CPM, which is a method to control costs and time.

Source: Difference Between PERT and CPM (with Comparison Chart) – Key Differences

Difference Between PERT and CPM

CPM vs PERTProject management can be understood as a systematic way of planning, scheduling, executing, monitoring, controlling the different aspects of the project, so as to attain the goal made at the time of project formulation. PERT and CPM are the two network-based project management techniques, which exhibit the flow and sequence of the activities and events. Program (Project) Management and Review Technique (PERT) is appropriate for the projects where the time needed to complete different activities are not known.

On the other hand, the Critical Path Method or CPM is apt for the projects which are recurring in nature.

The two scheduling methods use a common approach for designing the network and for ascertaining its critical path. They are used in the successful completion of a project and hence used in conjunction with each other. Nevertheless, the truth is that CPM is different from PERT in a way that the latter concentrates on time while the former stresses on the time-cost trade-off. In the same manner, there are many differences between PERT and CPM, which we are going to discuss in this article.

Content: PERT Vs CPM

  1. Comparison Chart
  2. Definition
  3. Key Differences
  4. Video
  5. Conclusion

Comparison Chart

Meaning PERT is a project management technique, used to manage uncertain activities of a project. CPM is a statistical technique of project management that manages well defined activities of a project.
What is it? A technique of planning and control of time. A method to control cost and time.
Orientation Event-oriented Activity-oriented
Evolution Evolved as Research & Development project Evolved as Construction project
Model Probabilistic Model Deterministic Model
Focuses on Time Time-cost trade-off
Estimates Three time estimates One time estimate
Appropriate for High precision time estimate Reasonable time estimate
Management of Unpredictable Activities Predictable activities
Nature of jobs Non-repetitive nature Repetitive nature
Critical and Non-critical activities No differentiation Differentiated
Suitable for Research and Development Project Non-research projects like civil construction, ship building etc.
Crashing concept Not Applicable Applicable

Definition of PERT

PERT is an acronym for Program (Project) Evaluation and Review Technique, in which planning, scheduling, organizing, coordinating and controlling uncertain activities take place. The technique studies and represents the tasks undertaken to complete a project, to identify the least time for completing a task and the minimum time required to complete the whole project. It was developed in the late 1950s. It is aimed to reduce the time and cost of the project.

PERT uses time as a variable which represents the planned resource application along with performance specification. In this technique, first of all, the project is divided into activities and events. After that proper sequence is ascertained, and a network is constructed. After that time needed in each activity is calculated and the critical path (longest path connecting all the events) is determined.

Definition of CPM

Developed in the late 1950s, Critical Path Method or CPM is an algorithm used for planning, scheduling, coordination and control of activities in a project. Here, it is assumed that the activity duration is fixed and certain. CPM is used to compute the earliest and latest possible start time for each activity.

The process differentiates the critical and non-critical activities to reduce the time and avoid the queue generation in the process. The reason for the identification of critical activities is that, if any activity is delayed, it will cause the whole process to suffer. That is why it is named as Critical Path Method.

In this method, first of all, a list is prepared consisting of all the activities needed to complete a project, followed by the computation of time required to complete each activity. After that, the dependency between the activities is determined. Here, ‘path’ is defined as a sequence of activities in a network. The critical path is the path with the highest length.

Key Differences Between PERT and CPM

The most important differences between PERT and CPM are provided below:

    1. PERT is a project management technique, whereby planning, scheduling, organising, coordinating and controlling uncertain activities are done. CPM is a statistical technique of project management in which planning, scheduling, organising, coordination and control of well-defined activities take place.
    2. PERT is a technique of planning and control of time. Unlike CPM, which is a method to control costs and time.
    3. While PERT is evolved as a research and development project, CPM evolved as a construction project.
    4. PERT is set according to events while CPM is aligned towards activities.
    5. A deterministic model is used in CPM. Conversely, PERT uses a probabilistic model.
    6. There are three times estimates in PERT, i.e. optimistic time (to), most likely time ™, pessimistic time (tp). On the other hand, there is only one estimate in CPM.
    7. PERT technique is best suited for a high precision time estimate, whereas CPM is appropriate for a reasonable time estimate.
    8. PERT deals with unpredictable activities, but CPM deals with predictable activities.
  1. PERT is used where the nature of the job is non-repetitive. In contrast to, CPM involves the job of repetitive nature.
  2. There is a demarcation between critical and non-critical activities in CPM, which is not in the case of PERT.
  3. PERT is best for research and development projects, but CPM is for non-research projects like construction projects.
  4. Crashing is a compression technique applied to CPM, to shorten the project duration, along with the least additional cost. The crashing concept is not applicable to PERT.

Video: PERT Vs CPM


The difference between these two project management tools is getting blurred as the techniques are merged with the passage of time. That is why, in most projects, they are being used as a single project. The primary point that distinguishes PERT from CPM is that the former gives the extreme importance of time, i.e. if the time is minimized, consequently the cost will also be reduced. However, cost optimization is the basic element, in the latter.

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Understand the difference between Lead-Lag, Float/Slack and Buffer Management

Over many years of my training experience, I have found that people are confused with the following project management terminologies. I have put my best effort to clarify these terms.

Source: Understand the difference between Lead-Lag, Float/Slack and Buffer Management

Over many years of my training experience, I have found that people are confused with the following project management terminologies. I have put my best effort to clarify these terms. Please do share your feedback and comments for the benefits of the others.

1.      Lead and Lag are the duration unit of tasks. Lead is portrayed by negative (-) sign whereas Lag is by positive (+) sign. A lead is the amount of time whereby a successor activity can be advanced with respect to a predecessor activity whereas A lag is the amount of time whereby a successor activity will be delayed with respect to a predecessor activity.

Lead and Lag are decided by the Project manager based on the logical relationship between two tasks. For example, Hang a photo frame on the wall. In this case, consider you have the following tasks…

a.      Task A – Construct a wall

b.     Task B – Paint a Wall

c.      Task C – Hang a photo frame

Here, Task B is a predecessor to Task C and it also required waiting time (Lag) before the successor task can start. Now the lag will be decided by the project manager based on expert judgment and other facilitation techniques in this case.

Hence, Lead and Lag are always imposed by the project managers on a critical or non-critical path based on task logical relationship.

2.      Float or Slack is again an activity duration unit where a task can be delayed without having impact on early start date of successor task (free float) or project duration (Total Float) or customer constraints date (Project float) but the difference here, it is not imposed by project manager manually rather they exist in network diagram because of the sequencing of the tasks.

Float or Slack can only exist on the non-critical path.

Formula: Float = LS-ES or LF – EF

3.      Buffer or Reserve Or Padding are used in project management as a risk response strategy. They are again manually decided by project managers based on expert judgment or other facilitation techniques with the team and other stakeholders.

In the Project network diagram on the critical path, when we put buffer (Project Buffer) at the end of the network, it is for the purpose of mitigating the unknown-unknown risk and hence to protect the project schedule for delay from unidentified risk.

When we put Buffer on a non-critical path (Feeding Buffer) it is again for risk of delay to task on the non-critical path which has an impact on the task on the critical path because of their relationship/constraints.

To summarize, Float, Lead/Lag and Buffer are not the same. Float for the task cannot be decided by project manager whereas Lead/Lag and Buffer can be decided by him with other’s help.

Lead/Lag can exist on both critical or non-critical paths the same as Buffer but the difference is Buffer can also exist at the end of the critical path as oppose to Lead/Lag.


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Precedence Diagramming Method (Activity on Node Method) in Scheduling | PM Study Circle

A Precedence Diagramming Method (PDM) is a graphical representation technique. It shows the inter-dependencies of activities and is used in schedule

Source: Precedence Diagramming Method (Activity on Node Method) in Scheduling | PM Study Circle


A Precedence Diagramming Method (PDM) is a graphical representation technique. It shows the inter-dependencies of activities and is used in schedule development. The other name for this technique is Activity on Node (AON).

We use this method in drawing the project schedule network diagrams; for example, critical path networkcritical chain network diagram, and others.

The Precedence Diagramming Method shows activity relationships. Hence, it is an important communication tool for stakeholders.

Precedence Diagramming Method (PDM)

The Precedence Diagramming Method is made of rectangles, known as nodes. These boxes show the project activities. An arrow connects two boxes and shows the relationship. Therefore, these diagrams are also known as Activity on Node (AON) diagrams.

Type of Dependencies in PDM

The PDM uses four dependencies:

  1. Mandatory Dependency
  2. Discretionary Dependency
  3. External Dependency
  4. Internal Dependency

Mandatory Dependency

This dependency is also known as hard logic. You cannot avoid it. Starting the next activity depends on it.

For example, you cannot install the ceiling until you build all the walls.

Discretionary Dependency

This dependency is also known as preferential or soft logic, it plays a role in optimizing resources.

For example, you can construct the four walls in any sequence. However, if constructing them in a certain sequence is beneficial you build them in that order.

Here, you can change the sequence of activities as per your preferred logic.

External Dependency

The project management team has no control over an external dependency.

For example, you may need government approval before starting the next activity.

Internal Dependency

These are dependencies are within the control of your project or organization.

For example, you cannot get a resource until it is free from another project.

Dependency Relation

The Precedence Diagramming Method uses four relationships:

  1. Finish to Start (FS)
  2. Finish to Finish (FF)
  3. Start to Start (SS)
  4. Start to Finish (SF)

Finish to Start (FS)

Here, the next activity cannot start until the first is complete. This is the most common relationship in PDM.

Finish To Start (FS) Relationship

For example, to paint a wall you first you have to construct it. In this case, the first activity is building the wall and the second activity is painting. You cannot start painting the wall until the wall is ready.

Finish to Finish (FF)

Here, you cannot complete the next activity until the first is finished. Put simply, both activities should be finished simultaneously.

Finish To Finish (FF) Relationship

For example, let us say that you are coding a program for a client. The client gives you the features after completing a milestone. You cannot finish coding until you get the client’s complete requirements. Here, both activities should be finished simultaneously.

Start to Start (SS)

Here, the next activity cannot be started until the first starts. Both activities should start simultaneously.

Start To Start (SS) Relationship

Suppose you have to apply a coating on a wall, but the wall must be cleaned in order to apply it.

Therefore, one team will clean the wall and second team will coat it. Both activities can start simultaneously.

Start to Finish (SF)

Here, you cannot finish the next activity until the first starts.

Start To Finish (SF) Relationship

For example, let us say you are moving into a new home and your old home has to be demolished. In this case, you cannot move into your new home until it is ready. Hence, the second activity (construction of the new home) must be finished before the first activity starts (moving into a new home).

Put simply, you are moving into your new home. You cannot start vacating your old home until the new house is ready.

Although this relationship is rare, you must understand all the dependencies. It will help you draw the network diagram and develop the project schedule.

This concludes the precedence diagram method.

You may hear the term Activity on Arrow (AOA). This is a less commonly used technique in diagramming methods. The AOA method is a special case of the Precedence Diagramming Method.

AOA diagram only uses the Finish to Start relationship. It shows the duration over the arrows, that is why many experts call this diagramming method the Activity on Arrow diagram. PERT is an example of this technique.

There is a difference between the AON and AOA diagram. The AOA diagram emphasizes milestones (events), and the AON diagram emphasizes tasks.

How to Draw a Precedence Diagram

To draw a PDM, you will break your Work Breakdown Structure down to the activity level.

Then you will create a table, list all activities, and sequence the activities.

The next step is to add relationships to each activity. You will add what activity comes next.

Finally, you will draw the diagram.

Benefits of Precedence Diagramming Method

This method offers many benefits to project management:

  1. It helps you find relationships and dependencies among activities. This helps you in planning and avoiding risks. If any task is missing, you can easily identify it.
  2. You can find critical activities and focus on them. Any delay in critical activities will delay your schedule.
  3. A project schedule network diagram is a good communication tool. Stakeholders can visualize activities and understand the schedule.
  4. Without the Precedence Diagram, you cannot develop your project schedule.


The Precedence Diagram Technique has an important role in project management. Your project schedule depends on it and it is a good communication tool. It is commonly referred to as AON, where nodes represent activities. The other PDM is AOA, where nodes represent milestones and duration is shown on the arrow.

This topic is important for the PMP exam. You may see one or two questions on this topic.

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Design of Experiments – Project Management Knowledge

Source: Design of Experiments – Project Management Knowledge

  • Statistical method for identifying factors which may influence a product or the processes
  • May be used in quality to determine type and number of tests to be executed in control
  • Represents a manner in which many product and process factors can be examined as opposed to attacking one at a time
  • Considers cost impact on changes in processes

When it comes to quality planning, there are several tools that can be used by project managers and one of them is the design of experiments (DOE). It is a technique that is used to identify different factors that can influence different aspects of the process or product during the time when it is being developed.  It is used during the quality planning management  to determine the type of tests and the different impacts they have on the cost of quality.

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Critical Path vs Critical Chain – PMP Exam Concepts

Source: Critical Path vs Critical Chain – PMP Exam Concepts

Critical Path vs Critical Chain

Critical path and critical chain are both methods of project scheduling.

Critical Path

The critical path method calculates the early start and finish dates and late start and finish dates for all schedule activities.

The critical path method involves performing a forward pass analysis and a backward pass analysis through the project schedule network paths. The forward pass determines the early start (ES) and early finish (EF) dates (ES + duration (DU) = EF). The backward pass determines the late start (LS) and late finish (LF): (LF – DU = LS).

The critical path is the longest path through the schedule with either zero or negative total float.

Critical activities are those schedule activities on the critical path. Near-critical activities are those schedule activities with very little total float.

Critical Chain

The critical chain method is a technique that modifies the project schedule to account for limited resources by adding duration buffers that are non-work schedule activities to maintain focus on the planned activity durations.

Critical chain is completed after determining critical path by entering resource availability and the resulting schedule produces a resource-constrained critical path, which is usually altered from the original. Critical chain focuses on managing remaining buffer durations against the remaining durations of task chains.


The critical path method (CPM) is a popular approach to project scheduling that considers the amount of float on project activities. Critical chain takes CPM a step further by adding time buffers to account for limited resources.