A Guide to Dependencies, Constraints and Assumptions (Part 2): Managing Constraints

What are constraints?

Constraints are very similar to dependencies in that they also have an impact on the project’s delivery. However, the two concepts are not the same, as dependencies are about the order or sequence of tasks. Whereas constraints are limitations to the project, such as the limited availability of resources like time and funds. A huge part of a project manager’s job is to balance project constraints. The PMI differentiates between six competing constraints:

  • Scope
  • Schedule
  • Budget/Costs
  • Quality
  • Resources
  • Risks

‘Competing’ means that each constraint has an impact on one or more of the other constraints. So let’s say you’re building a house: Your cement delivery is one week late because the supplier has a shortage of manpower right now. You can’t start laying your house’s foundation until the cement arrives, so your project’s schedule is delayed for one week. This delay has a direct impact on your budget because you will have to pay the construction crew one extra week. The change in the schedule has a direct impact on the costs and also an impact on the resources. 

The Magic Triangle (aka Iron Triangle or Project Triangle)

The project triangle, often called ‘magic triangle’ 

Why is it so important to manage constraints?

Project managers have to carefully identify, assess and manage constraints because they have a direct impact on whether or not the team can finish the project on time, within budget and within scope. Constraints are restrictions, which means that you have to take them into account when making project decisions from the very start. The clearer you define the constraints the easier will it for your team to work around them. Just like dependencies, constraints serve as a guide to help you plan your projects more accurately. Which is why they can’t be vague, you need to define them clearly and communicate it to your team. A bad practice example would be: “We have to finish the project by around the third quarter of the year.” This time limit is extremely vague, does it mean the project must be completed by the beginning of July or by the end of September? A better way to phrase it: “We have to finish the project by July 23rd and no later.” This is precise and leaves no room for interpretation, thus it helps your team put the project into perspective and focus on getting things done on time.

How to manage constraints more effectively

Managing constraints can be challenging, but it is possible to plan your project around them and not let them affect your project’s schedule, budget or scope too much. Here are a few best practice tips that help you manage constraints better:

  1. Make a list of all constraints that could affect your project. Documenting everything makes sure that you won’t overlook any constraints.
  2. Include the biggest constraints in your project charter and/or your project scope statement. This ensures that everyone on the team has access to the information.
  3. Communicate with important stakeholders, particularly the project sponsor and upper management. Be open about the constraints the project is facing and how important it is to not just manage risks, but all constraints.
  4. Constantly monitor and assess constraints. Sometimes constraints might change during the course of the project, or they might even disappear. For example, a past legal regulation might have been overturned and does not apply to your project anymore. Keep changes to a minimum though, because while they can have positive effect, changes can also have a negative impact on your project. The keyword here is ‘scope creep’.

Stay tuned for more: The next part of this series will be all about project assumptions and how they differentiate from dependencies and constraints.