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Milestone Scheduling Approach

The milestone approach is one of the most undervalued scheduling tools. Reactive management of projects and the absence of planning outputs-oriented processes are among the main reasons why the management of the milestones has been reduced to a representation of a deadline.

This article describes what is a milestone, how to enhanced communication and control through progress reports. This article aims to show how to use the milestone approach at different levels within a project.

What is a milestone?

According with the PMBOK, “A milestone is a significant point or event in a project”.

Managing Successful Projects with PRINCE2 mentions, “A milestone is an event on a schedule which marks the completion of key activities”. These key activities could be the “completion of a Work Package, a technical stage or a management stage, or the trigger for a payment to a supplier”.

As a resume, we can say that a milestone is timeless activity used for monitoring and control purposes throughout the life of a project that act as a trigger point for go on /stop decisions, payments, control points, etc. A milestone should be SMART (Specific, Measurable, Achievable, Realistic, and Time bound).

What is the milestone scheduling approach?

The milestone scheduling approach is a technique for managing the project checkpoints. This technique allows us to view the current status of a project, identify deviations, and detect errors in the data-collection methods of progress reports. In addition to this, it’s an excellent tool to communicate the status of project to stakeholders that are external to the project team.

The scheduling approach is composed by 3 main documents: Milestone List, Milestone Charts and Milestone Reports.

Milestone List

It is a good practice to group the milestones in a milestone list that works as a reference point for future decisions such a change request, go on/stop decision, etc.

A milestone list is a list of all project milestones and its main characteristics. The milestone list should clarify questions such as:

  • What is the purpose of the milestone?
  • Which are the assumptions and constraints in relation with the milestone?
  • Where are the sources of the milestone?
  • Is it mandatory or optional?
  • Is it based upon historical information or a contract?
  • When is the deadline?
  • Which is the reason behind the deadline?
  • Who is responsible?
  • Which deliverables could impact the milestone?

While there is no ’correct’ number of milestones or duration between them, they lose their value when there are too many or too few. Breaking the plan into intervals associated with a milestone allows the Project Manager to define an early indication of risks associated with schedule.

Milestone Charts

A Milestone Chart is a summary schedule that identifies the major schedule milestones in a chart.


The milestone chart provides a clear picture of the decision points of the project. Among the benefits of the milestone chart are:

  • Allows promoting the project (along with the scope statement) between relevant stakeholders.
  • It is a reference point for contracts with subcontractors and vendors.
  • Enhanced a product delivery approach.
  • Keep focus on value creation.
  • Avoid excessive use of information.

Milestone Reports

Milestone reports are a graphical concise way of advising the status of the project and should encourage the project team to meet the targets. This is especially important if milestones are related to large tranches of progress payments.

Figure 2 shows a milestone report. The x-axis represents the project calendar and the y-axis is the main reporting periods in terms of time. If both axes are drawn to the same scale, a line drawn from the top left-hand corner to the bottom right-hand corner will be at 45º to the two axes. The planned milestones are on the y-axis.


As the project progresses, the preliminary dates of achievement of the milestones are inserted allowing the Project Manager to visualize any slippage. This should trigger a management action to ensure a back on track or recommend a change request.

A pattern is created as the programmed slippage of each milestone is marked, which acts not only as a historical record of the slippages but can also be used to give a prediction of future milestone movements.

Milestones have 4 patterns that are illustrated in the Figure 2. The patterns are:

  • Purple line shows a milestone that reaches its end without any slippage (the slope is zero).
  • Green line represents a constant delay of the target date (the slope is greater than zero).
  • Blue line illustrates a milestone that was reached ahead of the target date (the slope is less than zero).
  • Red line is an example of a milestone that was delayed and then stopped the slippage.

It’s important to recall that:

  • If a milestone is not on the critical path, it may well slip on the slip chart without affecting the next milestone.
  • If two adjacent milestones on the slip chart are on the critical path, any delay on the first one must cause a corresponding slippage on the second.


The milestone scheduling approach allows the Project Manager to be focus on the delivery of products, value creation and communication while controlling the project and reporting to the key stakeholders.

The Project manager has to develop instruments that allow him to be focus of communication and value creation and the milestone scheduling approach is one of these.


  1. A guide to the Project Management Body of Knowledge – PMBOK® Guide. 5Ed. PMI. Pennsylvania, 2013.
  2. Practice Standard for Scheduling. 2Ed. PMI. Pennsylvania, 2011.
  3. Managing Successful Projects with PRINCE2. TSO. Norwich, 2009.
  4. LEACH, Critical Chain Project Management. 2Ed. Artech House. Norwood, 2005.
  5. VANHOUCKE, Mario. Project Management with Dynamic Scheduling Baseline Scheduling, Risk Analysis and Project Control. 2Ed. Springer. Berlin, 2013.
  6. LESTER, Albert. Project Planning and Control. 4Ed. Elsevier. Oxford, 2003.