What is Project Schedule? Importance, Creating, Goal

  • Post last modified:11 July 2021
  • Reading time:11 mins read

What is Project Schedule?

The project schedule is the management tool that merges all the work tasks to be performed, their relationships, their estimated durations, and their assigned resources to a calendar.

Scheduling also enables you to identify the key activity sequence (critical path) determining the length of the project and display departmental work loading and hence facilitate departmental planning. It provides the basis for more detailed scheduling.

Scheduling enables analysis and forecasting which show priorities for procuring equipment, material, labor and services. It analyzes complex work areas with many interrelated activities through network analysis. It also facilitates long-range planning and future resource allocation.

As mentioned above, the project schedule is often referred to as the “project plan” in error. While not technically correct, it is easy to understand why this term is often used. The project schedule serves as the chief integration point for most, if not all, of your project planning efforts.

The project schedule reflects (or should reflect when the schedule development process is complete) all the following:

  • Work Breakdown Structure (WBS)
  • Resource plan
  • Work estimates
  • Key milestones
  • Responsibility assignments (RASIC)
  • Quality management plan
  • Risk management plan
  • Communications management plan
  • Procurement management plan
  • Staff management (training) plan

Project Schedule Definition

Project scheduling has been defined by the Project Management Body of Knowledge as an output of a schedule model that presents linked activities with planned dates, durations, milestones, and resources.

The term linked activities is important because it illustrates the scheduling goal. Project scheduling defines network logic for all activities; that is, tasks must either precede or follow other tasks from the beginning of the project to its completion.


Why Project Schedule is Project Manager’s Weakness?

It’s funny really. The one activity that the common person associates with project management is planning, and the main output from this planning effort is a schedule. Yet, it is a challenge to find a project manager who can develop one accurately.

Although scheduling is one of the two primary technical aspects of project management, it is a common technical weakness of many project managers.

Well, I can state at least four reasons:

  • Lack of time for proper planning
  • Lack of education on the schedule development process
  • Lack of training with the scheduling software
  • A belief that a detailed schedule is not necessary

Goal of Project Schedule Development Process

The schedule development process should generate a project schedule that meets the following criteria:

  1. Complete
  2. Realistic
  3. Accepted
  4. Formal

Complete

The schedule must represent all the work to be done. This is why the quality and completeness of the WBS is so important.

Realistic

The schedule must be realistic with regard to time expectations.

Accepted

The schedule must have “buy-in” from team members and stakeholders.

Formal

The schedule must be documented and formalized.


Inputs for Building a Project Schedule

The first step in building a schedule is to review the key inputs. Five inputs for building a project schedule are:

  • Work Breakdown Structure: List of organized tasks, the work to be done.

  • Effort estimates: Amount of effort and time each task will take.

  • Task relationships: The logical dependencies that exist between work tasks.

  • Resources: The actual personnel and equipment needed to perform the work between work tasks.

  • Risk responses: Measures taken to deal with the uncertainty surrounding effort and resource estimates. Usually, in the form of additional time (contingency buffer) added to the schedule.
Building a Project Schedule
Source: Project Management Book – Gregory M. Horine

Creating a Project Schedule

Key steps involved in building a project schedule are;

  1. Identify the work tasks (WBS)
  2. Estimate the effort for each work task
  3. Determine task relationships (network diagram)
  4. Assign resources
  5. Develop preliminary schedule
  6. Perform “reality” check
  7. Shorten the schedule
  8. Account for risk responses
  9. Walk-through the schedule
  10. Finalize schedule

Identify the work tasks (WBS)

Identify the work tasks that need to be performed.

Estimate the effort for each work task

Based on specific resource types, estimate the amount of effort each task will require.

Determine task relationships (network diagram)

Identify which tasks have to be done before others can begin and which tasks can be done at the same time (in parallel).

Assign resources

Assign the roles, personnel, and equipment that will perform each task.

Develop preliminary schedule

If you have not already, capture all these inputs using your preferred scheduling software.

Perform “reality” check

A key, often overlooked, step in the process to make your schedule realistic. This step includes a review of resource allocation and calendar setup.

Shorten the schedule

In this step, you determine the critical path and look for ways to reduce the time required to complete the critical path tasks.

Account for risk responses

If any of the risk responses includes adding a contingency buffer to any specific task or to the entire schedule, make sure to include this in the schedule too.

Walk-through the schedule

In this important step, the proposed schedule is presented for review and feedback. At a minimum, the schedule should be closely reviewed by the core project team first, and then by the key stakeholders (management, customers)

Finalize schedule

Incorporate feedback from stakeholders; make any adjustments for actual resource assignments, final risk responses, and success factor tradeoffs; get formal acceptance of schedule.

Let’s take a closer look at a few of the key steps separately.


Building the Preliminary Project Schedule

We are ready to build our initial schedule. There are a few keys to remember here:

  • Use scheduling software and get properly trained in how to use it.

  • For each task you want to schedule, you need to enter the following information:
    • Task name
    • Estimated effort
    • Predecessor task
    • Assigned resource

  • Understand the relationship between work, duration, resources, and productivity.

  • Using the scheduling software, locate the critical path. Often, the software will differentiate the tasks that comprise the critical path in some way, such as showing these tasks in red font.

  • While the overall schedule development process should be a team-based activity, a single person generally performs the construction of the actual schedule, due to the nature of the software.

Value of Scheduling Software

In case you are not an advocate of scheduling software, or you need to help convince someone else in your organization, please note the following benefits provided by scheduling software:

  • Critical path analysis
  • Project and resource calendars
  • Schedule calculation
  • Resource leveling
  • Baseline management

Perform “Reality” Check

In this step, we need to make sure the schedule is reasonable and is aligned with the organizational culture. The primary checkpoints are to check for proper allocation of resources and to check for proper use of calendars.

When checking for proper allocation resources, you want to do two things: remove unrealistic work allocations and optimize the use of your resources.

This activity is commonly referred to as resource-levelling. Most scheduling software systems provide a function to do this for you, but proceed with caution—the software does not always get this right. As a result, you can have a less than optimal schedule.

The three common responses to resource over-allocation situations are:

  • Utilize other resources. Assign one or more of the affected tasks to an available resource.

  • Establish a predecessor relationship. If Joe is the one who must perform each task, make the start of one task dependent on the finish of the other(s).

  • Modify the priority level of one or more of the tasks and let the software perform its resource leveling function.

To check for proper use of calendars, verify the following:

  • Are non-working days accounted for (holidays, weekends)?

  • Are the number of work hours per day consistent with the organization’s expectation? Are eight hours of productivity per day assumed or something different?

  • For part-time resources or resources with special work schedules, are individual calendars assigned to them that reflect this reality?

Shorten the Schedule

On most projects, your preliminary schedule will not be the schedule presented to the stakeholders for approval. Due to either stakeholder expectations or an external deadline that must be met, an effort must be made to compress or “shorten” the schedule without reducing the scope of the project. The key to this effort is the critical path.

The critical path determines the earliest (the soonest) your project can be completed given the current task relationships and estimated durations. As a project manager, you want to be very clear about which tasks comprise the critical path for two reasons:

  • The critical path determines the earliest (the soonest) your project can be completed given the current task relationships and estimated durations.

  • As a project manager, you want to be very clear about which tasks comprise the critical path for two reasons:

The common techniques to consider are:

  • Crashing: Adding resources to critical Certain activities cannot be path activities only.

  • Fast tracking: Performing critical path activities in parallel.

  • Process improvements: Gaining productivity increases based on different work processes, technologies and/or machinery.

  • Limited Overtime: Increasing the number of hours per day or week available to work on project tasks.

Walk Through the Schedule

In our pursuit of both a more realistic schedule and a schedule that our stakeholders feel ownership for, we need to walk through the schedule with at least two groups—and if at all possible get a third quality-based review.

  1. Review with project team
  2. Quality review
  3. Review with project stakeholders

Review with project team

First, present the proposed schedule to your project team. Seek their feedback on all aspects and make any necessary adjustments.

Quality review

This review is not always possible, but whenever possible, have an experienced and knowledgeable project scheduler review your proposed schedule before you submit it to your stakeholders.

Review with project stakeholders

Present the proposed schedule to key stakeholders. Seek feedback and questions on all aspects: verify resource assignments, risk responses, key milestones, and so forth.


Presenting the Schedule

One element of project planning and project management that is often overlooked is effectively communicating the project schedule to the various project stakeholders.

Although presenting a detailed, tabular view of the schedule to the core team is acceptable, the use of visual summary representations of the schedule is highly recommended when presenting the schedule to other stakeholders.

The common methods of presenting a project schedule summary are:

  1. Milestone Chart
  2. Gantt chart
  3. Network diagram
  4. Modified WBS

Milestone Chart

  • This is a bar chart that shows start and end dates, major deliverables, and key external dependencies.
  • Milestone tables are also used (same information, no bar chart).

Gantt chart

  • This is a bar chart that shows the various levels of the WBS.
  • Usually does not generally show interdependencies.

Network diagram

  • A network diagram uses nodes and arrows. Date information is added to each activity node.
  • For presentations, the summary task level of the WBS is generally used. Otherwise, a network diagram is best suited for wall display.

Modified WBS

  • Uses the project WBS organization with status information added to each node.
  • Similar to network diagram type representations.

Importance of Project Schedule

In addition to providing this vital integration role, the project schedule is important to the project manager.

Following are the importance of the project schedule:

  1. Drives project budget
  2. Drives resource schedule
  3. Essential for managing expectations
  4. Allows project performance to be measured
  5. Provides for “what-if” analysis capabilities

Drives project budget

Since most of your project costs are a factor of time, the project schedule is the main driver for your project budget. If the schedule is inaccurate, your budget is likely incorrect too.

Drives resource schedule

Your schedule drives the timing of your resource needs. Especially in organizations where resources are shared across projects or centrally managed, the accuracy of the schedule is key to efficient resource management.

Essential for managing expectations

With a well-developed schedule, you have the best tool for managing stakeholder expectations regarding the schedule-cost-quality equilibrium. A well-developed schedule illustrates the “earliest” date a project can be completed given the project’s current requirements and constraints.

This is an invaluable tool when negotiating the final schedule with senior management or customers and when assessing the impact of any change to equilibrium factors during the execution of the project.

Allows project performance to be measured

With a well-developed and approved project schedule, you now have the capability to establish a baseline for how the project is actually performing.

Provides for “what-if” analysis capabilities

Another important ability that a well-developed schedule provides is the ability to perform “what-if” analysis during the execution of the project. Over the course of a project, things happen that can negatively impact project performance.

At these times, you will often be asked what corrective actions can be taken to possibly get the project back on schedule. Without a well-developed schedule, you will not be able to quickly determine the impact of implementing a given schedule compression technique, such as fast-tracking, crashing, or limited overtime.


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