Developing the Project Schedule

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Now that the estimates for the activities are completed, it's time to work some magic and see how long the entire project will take. The project manager specifically pursues the start date, and more importantly, the completion date. Projects that don't provide realistic schedules aren't likely to get approved. Or worse, the projects will get approved, but they will most likely fail, as the project team will not be able to meet the unrealistic schedule.

The creation of the project schedule is iterative. It's rare for a schedule to get created, approved, and implemented without some iterative examination, arrangement, and management input-though on smaller projects it may be possible. When activity list updates, constraints, assumptions and other inputs are considered, it's easy to see why scheduling can become complex.

Revisiting the Project Network Diagram

The PND illustrates the project. Recall that the PND shows the sequence of activities and the relationship between activities. The PND is important during schedule creation because it allows the project manager and the project team to evaluate the decisions, constraints, and assumptions that were made earlier in the process to determine why certain activities must occur in a particular order.

Hard logic and soft logic must be evaluated to confirm that the decisions and logic are feasible, accurate, and fit within the expected completion of the project. The following illustration is a simple PND for a small project.

Relying on Activity Duration Estimates

Another key input to schedule creation is the activity duration estimates. Makes sense, right? The project manager needs to know how long the whole project will take, so the activity duration estimates will help calculate that number. Recall, however, the range of variances for each activity-these possible variances need to be accounted for in the actual project schedule creation. We'll discuss the schedule creation in a few moments.

Considering the Resource Requirements

The identified resource requirements will affect the project schedule. Remember the difference between duration and effort? Duration is how long the activity will take, effort is the labor applied to the task. For example, painting a building may take 80 hours to complete with two workers assigned to the job. Add two more workers and now the work will take only 40 hours.

The duration in the preceding example is 40 hours to complete the painting, but there will be 160 hours of effort on the activity. At some point in the work, the 'duration to effort ratio' becomes saturated, and adding additional laborers will actually become counterproductive. This is subject to the law of diminishing returns. The following illustration demonstrates the previous example.

Considering the Resource Pool Availability

In a perfect world, all of the needed resources for a project would be available whenever the project manager says so. In the real world, and on your PMP exam, the availability of project resources fluctuate due to demands of other projects, demands of ongoing operations, personal lives, vacations, sick days, and more.

The availability of the project pool must be evaluated. If certain activities require a worker with a highly specialized skill, these activities are resource-dependent. Should the worker not be available for the timeframe of the required activity, one of several things must happen:

• The project manager must negotiate to make the resource available for the activity in the project schedule.

• The activity must be moved in the schedule for when the resource is available.

• The activity, and possibly the project, must wait for the resource to become available.

• The project may incur additional costs by finding other resources to complete the scheduled work.

Exam Watch

When resources are needed but are not available, the project manager must negotiate to secure the resource. This may involve tradeoffs between projects or additional expenses as the activity is outsourced to a vendor to complete the work. The project manager does not want to delay the project waiting on a resource.

Considering the Calendars

There are two calendar types that will affect the project:

• Project calendar This calendar shows when work is allowed on the project. For example, a project may require the project team to work nights and weekends so as not to disturb the ongoing operations of the organization during working hours. In addition, the project calendar accounts for holidays, working hours, and work shifts that the project will cover.

• Resource calendar The resource calendar controls when resources, such as project team members, consultants, and SMEs are available to work on the project. It takes into account vacations, other commitments within the organization, or restrictions on contracted work, overtime issues, and so on.

The consideration of the project calendar and the resource calendar is mandatory to predict when a project may realistically begin and end. Figure 6-5 shows the project calendar setting from Microsoft Project. Keep in mind the PMP exam is not concerned with which PMIS system is used, but the understanding of the role of the PMIS.

Figure 6-5: Project calendars determine when the project work will take place.

Evaluating the Project Constraints

Constraints will restrict when and how the project may be implemented. Constraints are added to a project for a purpose, not just to rush the work to completion. It is important to understand why the constraint has been imposed. Here are a few common examples of why constraints exist:

• To take advantage of an opportunity to profit from a market window for a product or service

• To work within the parameters of expected weather conditions (for seasonal or outdoor projects)

• To adhere to government requirements

• To adhere to industry regulations, best practices, or guidelines

• To work within timeframes that incorporate the expected delivery of materials from vendors or other projects

Perhaps one of the biggest constraints is the predetermined project deadline. Imagine a company creating a product to take to a tradeshow. If the creation of the product is running late, the tradeshow isn't going to move so that the product has enough time to be completed for the show. There are four time constraints to consider:

• Start No Earlier Than (SNET) This constraint requires that the project or activity not start earlier than the predetermined date. Consider an activity to add software to an existing network server in a technology project. The project manager adds a 'Start No Earlier Than' constraint on the activity to ensure the activity begins on a Saturday when the server is not in use by the organization. The activity can begin any time after the preset date, but not before it.

• Start No Later Than (SNLT) This constraint requires the activity to begin by a predetermined date. For example, the creation of a community flower garden must 'Start No Later Than' May 15. The creation of the garden may, weather permitting, begin earlier than the preset date, but it must start by that date.

• Finish No Later Than (FNLT) This constraint requires the project or activity to finish by a predetermined date. For example, the installation of flooring tile in a restaurant must be finished by October 25 so the kitchen equipment can be installed. The constraint 'Finish No Later Than' is tied to the date of October 25. The activity can end sooner than October 25, but not after it.

• Finish No Earlier Than (FNET) This somewhat unusual constraint requires the activity to be in motion up until the predetermined date. Consider a project to create a special blend of wine. The wine must be aged a specific amount of time before the winemaking process can continue; the process requires a set amount of time so it may 'Finish No Earlier Than' the determined time. The activity can end any time after the preset date, but not before it.

Project constraints can also include milestones. The project sponsor may request, for example, a milestone for a deliverable within the project on April 28. Based on this milestone all of the work needed to create a deliverable must be scheduled against the expected due date. In addition, once these milestones are set, it's pretty darn tough to change them.

Milestone constraints can also be tied to activities outside of the project. Consider a scheduled walk-through with a customer on a construction project. Or consider the demands of a project to create a product or service by a scheduled milestone that another project within the performing organization is expecting.

Reevaluating the Assumptions

Assumptions are beliefs held to be true, but that may not necessarily be so. Assumptions, such as being able to have access to a building 24 hours a day, seven days a week, can wreak havoc on the project schedule if they are proved false. Consider a schedule that plans on working three shifts during a remodeling of an office building only to discover late in the project planning that the customer will not allow the work to happen during daytime hours. Assumptions factored into the project should be documented and accounted for.

Exam Watch

The 'Start No Earlier Than' and the 'Finish No Later Than' constraints are your best bets for exam answers since these are the most common constraints. Remember that constraints can be tied to individual activities within the project, or to the entire project.

Considering Leads and Lags

Leads and lags are values added to work packages to slightly alter the relationship between two or more work packages. For example, a finish-to-start relationship may exist between applying primer to a warehouse and applying the paint. The project manager, in this scenario, has decided to add one day of lead-time to the work package painting the warehouse. Now the painting can begin one day before the priming is scheduled to end. Lead time is considered a negative value because time is subtracted from the downstream activity to bring it closer to the start of the project.

Lag time is waiting time. Imagine a project to install wood floors in an office building. Currently, there is a finish-to-start relationship between staining the floors and adding a layer of shellac to seal the wood floors. The project manager has elected, because of the humidity in the building, to add two days of lag time to the downstream activity of sealing the floors. Now the shellac cannot be applied immediately after the stain, but must wait two additional days. Lag is considered a positive value since time is added to the project schedule.

The following illustration shows the difference between lead and lag. Leads and lags must be considered in the project schedule since an abundance of lag time can increase the project duration. An abundance of lead time, however, may increase risks.

Evaluating the Risk Management Plan

We'll discuss risk and risk management completely in Chapter 11. For now, know that risks can alter the project schedule-for better or for worse. This isn't difficult to see. A risk in the project may be identified as delays from the vendor for the equipment needed to complete the project. The response to this risk, should it happen, may be to secure an alternate vendor that charges slightly more for the same equipment but has it in stock. The delay of the equipment with the original vendor may throw the project off schedule, and the additional time to find, purchase, and ship the needed equipment could also add extra time to the project.

Examining the Activity Attributes

The activity attributes can have a direct impact on the project schedule. Some activities are effort driven, which means more effort can reduce the duration. Other activities are of fixed duration-that is, additional effort does nothing to reduce their expected duration. Activity attributes are the characteristics of the work to be completed, including

• Person(s) responsible for completing each work package

• Where the work will take place (building, city, outdoors)

• Type of activity (electrical, technical, supervised, and so on)

• When the activity must take place (business hours, off-hours, more unusual times)

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