No project happens in a vacuum. Projects are influenced by and are dependent on the environment in which they are taking place – both the corporate environment and the wider environment outside the company.
Dependency: The relationship that defines the order in which tasks are carried out. Task B is dependent on Task A if the start or finish date of Task A must be reached before Task B can be started.
Constraint: Something that limits your options.
Dependencies can occur inside and outside the project, and inside and outside the company. The following table shows the four different types of dependency and some examples.
Another way of defining dependencies
Dependencies can also be ‘upstream’ or ‘downstream’. An upstream dependency is one where something else must happen before your project can start something i.e. you are waiting for a task to complete before starting work. A downstream dependency is something your project must deliver before something else can start i.e. someone else is waiting for you to complete tasks before they can begin work.
Constraints are similar to dependencies: they also impact how you can deliver the project. However, constraints are restrictions.
Project constraints could be factors that limit the time, resources or budget available to the project. Despite these, you still have to get the job done. Your challenge as a project manager is to find ways to deliver the project successfully within the constraints of your environment.
Identifying and assessing dependencies and constraints is a useful activity because many of your project decisions will be based on this information. If a dependency cannot be met, or if a constraint turns out to be too restrictive, this impacts your ability to deliver the project to the original plan.
Discussions around dependencies and constraints form a key part of your stakeholder engagement plans. You can use these discussions to set expectations about what your project can realistically achieve.
As project managers it’s often tempting to spend a lot more time on managing risks and issues than dependencies and constraints, but they are just as important and can have a massive impact on your project if you don’t manage them effectively. So how do you identify the dependencies and constraints for your project? We’ll be looking at a 5-step approach for doing that later this week.