Activity in box project management

Print

Network Diagrams and Resource Utilization

Introduction | Building a Network Diagram | Building an AIB Manually | AIB Simulation | Resource Constrained Planning | Resource Leveling | Adding or Modifying Resources | Summary

Introduction

Back to Top

Last week, we learned more about how to begin planning a project. We established the project charter, scope statement, work breakdown structure, and created the activity list. This week, we will talk about one of the most important aspects of project management—building a project schedule. We'll use a tool called a network diagram. There are several ways to build a network diagram. In this course, we will use the Activity in Box (AIB) method.

Building a Network Diagram

Back to Top

Now that we know what needs to be done, we need to sequence all of the activities and establish a network diagram. With the concept of a network diagram, you will be able to determine: (1) a project's scheduled completion time, (2) the slack or float of project activities, and (3) the critical path of your project.

Depending on the size of the project, the network may be built in pieces or as a large group. Either way, the step-by-step process to build a project network is used.

Build a Project Network (or a Partial Network)

1. Brainstorm activities that are required to complete the work packages, recording those activities on Post-it notes (without regard to sequencing).

2. Sequence those activities. Determine:

· The order of activities

· Which activities can occur at the same time

· Which activities need dependencies

1. Mandatory: requires the completion of another task.

2. Discretionary: a best practice or convenience. However, the subsequent task can begin if the discretionary dependency is not completed.

3. External: from another project or process, such as permits.

4. Internal: dependencies within the control of the project team.

3. Put the notes on a wall using the above information.

4. Build a network using the notes.

Next, the activities are assigned to the people who will be doing the work. They build duration estimates for the activities. The most accurate estimates are built using actuals from previous, similar projects. Then, the activities can be loaded into an automated scheduling tool like Microsoft Project. At that point, you will be able to determine the project's scheduled completion time, the slack or float of project activities, and the critical path of your project.

Building an AIB Manually

Back to Top

The good thing about using a tool like Microsoft Project is that it makes it easy to build a network diagram. The bad thing about the tool is that it makes it so easy; project managers don't always understand what they are doing, and cannot see when they have made a mistake. They just plug in the activities and move on.

It's like adding—you should first do it manually, and then use a calculator. Every project manager should know how to build an AIB manually so that he or she really understands the concepts before working in Microsoft Project. The project managers who understand it are much more effective and know how to use the tools more effectively. Those who do not know how to build a schedule manually often make mistakes and negatively impact a project's triple constraints. Practice is required for proficiency. Just like swimming, scheduling requires practice. You can read about it, but you must also practice it. Let's start to practice!

When you build the network manually, you will understand the concepts much better. This demonstration will walk you through the process of building an AIB manually. You will conduct a forward pass through a network to determine the early start and early finish of each activity. A forward pass is moving from start to finish of the project doing all necessary calculations. When you complete the forward pass, you know which activity will be the last one to complete. The Early Finish for that activity is the earliest date that your project can complete. Next, you will conduct a backward pass, by moving from finish to start, to determine the late start and late finish for each activity. Last of all, you calculate the slack/float for each activity.

Before you begin the AIB Simulation, let's define a few terms.

· Critical Path (CP): By definition, it is the path of activities from start to finish that all have a slack/float of 0. This path is especially important because if any of them complete later than scheduled, your project may not complete on time.

· Early Start (ES): Is the EARLIEST time the activity could possibly start.

· Early Finish (EF): Is the EARLIEST time the activity could possibly finish.

· Late Start (LS): Is the LATEST time the activity can start and not jeopardize the scheduled completion of the project.

· Late Finish (LF): Is the LATEST time the activity can finish and not jeopardize the scheduled completion of the project.

· Slack/Float or Total Slack/Float: Is calculated by: LF - EF, or LS - ES (both formulas will result in the same answer; if not, one of your numbers is incorrect). The slack/float tells you the number of days/weeks/months that an activity can begin late, or the number of extra days/weeks/months that an activity can take without impacting the completion time of the project. However, this time is shared by all of the activities on a path. If you use up all of your slack on an activity at the beginning of a path, subsequent activities will have less slack or no slack.

· Free Slack/Float: This represents how much an activity can slip without impacting a successor activity. This measure combined with slack determines which activities receive priority over resources.

AIB Simulation

Back to Top

Simulation

Activity in Box Diagram

Welcome to the Bi-Plane 3,000 Project! In this simulation, you will shadow Sandra, an experienced Project Manager, as she walks you through the construction of an Activity in Box Diagram. You will have opportunities to practice both the Forward and Backward Pass methods in depth. Together, you will cover the concepts of critical path and float.

Practitioner Corner

In the project management world, you are not likely to hear the term Activity in Box (AIB) unless you learned your project management from a textbook. In our world, we use the term Activity on the Node or AON. The calculations are the same but the set up is a little different. It is also the method employed by most project management software. So if you hear the term AON, network diagramming or precedence diagramming from project managers, you now know they are all talking about the same thing.

Resource Constrained Planning

Back to Top

Now that we have our project schedule established, we need to align the appropriate resources to accomplish the work. As resources are applied, conflicts may arise if resources become over-allocated.

A project manager can address resource conflicts in a variety of ways, but the first step is to realize there is a conflict. If the project team builds a schedule using a scheduling tool like Microsoft Project, the PM can run an Overallocated Resources report.

Once the over allocation is identified, there are several key strategies to address them: (1) resource leveling, (2) adding or modifying resources, and (3) changing the project.

Most methods for addressing resource conflicts cost the project something, either more money, less functionality, or an extension in the scheduled completion.

So why bother? In some cases, you have no choice—operational necessity. For instance, if your company has two bulldozers, and you need four on a particular week, you will have to address that resource conflict to complete both projects.

On other projects, resource conflicts take the form of people being over allocated. Sometimes, a team lead will say that is what nights and weekends are for but many people would strongly disagree. If people are overworked, something will suffer, either the quality of the product will decrease, and defects and re-work will increase.

Ultimately, it will result in personnel turnover. It costs a project time and money when people are replaced. If you make people miserable enough, they will leave either by quitting, getting sick, transferring, or just not working up to their capacity.

Addressing resource conflicts improves morale, which increases quality, reduces defects, reduces re-work, decreases team turnover, and increases team commitment.

Resource Leveling

Back to Top

The first method—resource leveling is the easiest to do if you are using an automated scheduling tool like Microsoft Project, but only if you understand what you are doing. You can also use the tool to try various what-ifs. For example, try plugging in new resources and see if their addition will change your scheduled completion time. If they are not working on a task on the critical path, their work will not even affect the project's scheduled completion. One must be careful with auto leveling in project management software, as it might change the program’s algorithm associated with the triple constraint.

This method smoothes out the peaks and valleys in your schedule without increasing your overall budget. If you choose a level only within available slack as an option when you level the resources, leveling the resources will not extend your project's schedule either. However, if there is not enough slack in your schedule, it will not correct all of your allocation problems, in which case, you will have to use another method to relieve the problem.

In summary, the benefits of resource leveling are:

1. Minimizes period-by-period variations by shifting tasks within their slack

2. Utilizes resources more efficiently

3. Resources do not have days with no work scheduled and other days with too much work

4. Does not increase budget

5. Does not have to change scheduled completion

Here is an example:

Click on image to enlarge

Before Leveling

After Leveling

Click here for Transcript

Before leveling: The resource is over allocated on 5/2, but not scheduled to do any work on 5/10. With this schedule, I work for 16 straight hours on 5/2, and have nothing to do on 5/10.

After leveling: MSP moved the excess work from 5/2 onto 5/10. With this schedule, I work a regular eight hours each day—much more palatable! However, as I mentioned before, sometimes there is not enough slack in the schedule to smooth out all of your activities, so let's look at some other options.

Adding or Modifying Resources

Back to Top

Adding people to a project must be approached carefully. Additional people are easier to absorb into projects that are well-documented. Adding personnel to well-defined tasks is straightforward when the plan is clear. Throwing people at projects that are in trouble, behind, and already managed poorly often results in an even bigger problem.

Adding resources increases the budget and rarely doubles the work completed. This is because additional people must be trained, which ties up their time and the time of a team member who is training them, and adds to the communication channels.

Modifying resources can take several forms: Assign a person with greater expertise or more experience to perform or help with the activity, and increase productivity through improved methods or technology.

Summary

Back to Top

Hide and Show

1. What are the different types of dependencies? Hide Answer

There are four different types of dependencies, including: Mandatory – requires the completion of another task. Discretionary – a best practice or convenience. However, the subsequent task can begin if the discretionary dependency is not completed. External – from another project or process. Internal – dependencies within the control of the project team.

Hide and Show

1. Hide Answer

The critical path is the path of activities that all have a slack/float of 0. It is important because if any of them complete later than scheduled, the project may not be completed on time.

Hide and Show

1. Which tasks would likely be part of the critical path for building a canoe? Why do the other activities have float/slack? Hide Answer

1. Obtain wood for boat

2. Build seats

3. Obtain oars or paddles

4. Cut and shape wood for boat body

5. Paint canoe with water sealant

6. Test boat in water

Hide and Show

1. Which tasks would likely be on the critical path for building a house? Why do the other activities have float/slack? Hide Answer

1. Obtain bricks

2. Paint Rooms

3. Install furnace

4. Obtain lumber

5. Wire for electricity

6. Obtain building permit

Hide and Show

1. What is float? Hide Answer

Float is the number of extra days/weeks/months an activity can take without impacting the completion time of the project. It is calculated by subtract Earliest Finish Time (EF) from Latest Finish Time (LF).

Hide and Show

1. Define an activity duration estimate. Hide Answer

The duration estimate for an activity is the time required to perform the work plus any associated waiting time.

Hide and Show

1. What are the benefits of resource leveling? Hide Answer

· Minimizes period-by-period variations by shifting tasks within their slack Utilizes resources more efficiently

· Resources do not have days with no work scheduled and other days with too much work.

· Does not increase budget

· Does not have to change scheduled completion

Back to Top

loading