Timeboxing and the Triple Constraint

Thinking of timeboxing in terms of the triple constraint is empowering for fact-based conversations that need to be had with the stakeholders. It's part of the great value-added you offer as a project manager.

This guest post from TenStep introduces the term "timeboxing", which is a common occurrence in the real world. It is a type of schedule constraint that is important and necessary to acknowledge. an easy way to remember what to do with such a time constraint is to think about the triple constraint. Present the trade-offs to stakeholders:

  • time
  • quality
  • resources

As to time, timeboxing may simply mean that time is fixed and not flexible, and that the trade offs will need to come from the other two factors. If that is the case, then the stakeholder will need to determine what is most important. In terms of quality, they can choose to forego or delay certain features. In terms of resources, they may be willing to provide additional manpower or money to help collapse the schedule.

The TenStep Method123 templates incorporate methods for into managing projects With pre-determined end dates, helping you to think through alternatives and to present them clearly - without re-inventing the wheel! You can find these templates at

Here's the TenStep post "Techniques to Manage Projects With Predetermined End-dates (Timeboxing) ":

In a perfect world, your project schedule and completion dates would be derived based on the amount of work to be done and the number of resources available. As you know, that is not always the case. Sometimes there is an end date by which the work must be completed. For instance, the end-date may be determined by a government regulation, a scheduled event or to coincide with another company initiative. This situation is referred to as a timebox, meaning you have a fixed amount of time to get the work done and the end-date is “boxed” in.

There is nothing wrong with having a fixed end-date. It can give everyone on the team a sense of urgency and focus. There may be a problem, however, if the project manager and team do not think they can get the work done by the deadline. In that case, the project manager needs to raise this as a risk. Potential risk plan actions include:

  • Assigning more resources to the project. Too many resources may have diminished value but this is usually the first place to start.
  • Having the team work overtime, with the understanding that overtime itself has a diminishing return, and that long-term overtime can actually have a negative effect.
  • Working with the stakeholders to scale back the required deliverables due by the deadline. This may include removing entire deliverables or functionality from required deliverables.
  • Determining whether some required deliverables and features can actually be delivered later than the due date. In these cases, a 90% solution may be viable at the due date, with the additional work completed soon after.

Important - Estimate the Amount of Schedule Risk

Even if your manager or sponsor has given you a fixed end-date, it is important to carefully build the schedule first as if you did not have the fixed end-date. If you do this first, it will give you a sense for how realistic it is to hit the fixed date. For example, let’s say you have a project that has to be completed in nine months. If you first create a “normal” schedule that shows the project will be complete in 9 ½ months, it would not be too much of a stretch to think you could complete the work in nine months. However, if you create a “normal” schedule and it shows the end date at 13 months, you will understand the difficulty and the risk associated with trying to get all of the work completed in the nine-month timebox. This does not mean that you will not have the nine month deadline. However, it gives you more information to have a fact-based discussion on the project risks and options that are available to you.

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