Mandatory vs. Discretionary Dependencies in Project Management: Key Differences Explained

The dependencies in project management are the relationship between two or more activities or tasks in which the completion of one activity is dependent on the completion of another. Managing and understanding these dependencies is important in delivering the project efficiently and effectively. There are two types of dependencies in project management: mandatory and discretionary.

Mandatory Dependencies

They are also known as hard logic or hard dependencies. They are a fundamental aspect of the work and cannot be changed. These dependencies are based on the physical or logical relationship between tasks and the order in which they must be completed. For example, the installation of a foundation must be completed before building construction can begin. Mandatory dependencies are usually easy to identify because they are based on the nature of the work and the inherent dependencies between tasks.

Discretionary Dependencies

Soft logic, also known as discretionary dependencies or preferential logic, refers to the relationships in project management that are based on best practices, preferences, or expert judgment rather than mandatory requirements.

Discretionary dependencies are often more flexible than mandatory dependencies and can be adjusted based on the needs and priorities of the project. However, project managers must be careful while considering the potential consequences of changing discretionary dependencies.

Difference Between Mandatory Dependencies and Discretionary

Following is the list of the main differences between mandatory dependencies and discretionary dependencies:

Sequence

Mandatory dependencies must be completed in a specific order or sequence, while discretionary dependencies can be completed in any order as long as the overall project schedule is not impacted.

Flexibility

Mandatory dependencies are inflexible and must be followed, while discretionary dependencies are more flexible and can be adjusted as needed.

Impact on Project Schedule

Mandatory dependencies can significantly impact the project schedule, as they must be completed in a specific order. On the other hand, discretionary dependencies can be completed at any time as long as they do not impact the overall project schedule.

Importance

Mandatory dependencies are typically considered more critical to the project, as they must be completed in a specific order to ensure the project's overall success. Discretionary dependencies are less critical, as they can be completed at any time as long as the overall project schedule is not impacted.

Changes

Changes to mandatory dependencies can be more complex and require more careful planning and coordination, as they can significantly impact the project schedule. Changes to discretionary dependencies are generally easier to manage as they have less impact on the overall project schedule.

Example for Mandatory Vs. Discretionary Dependencies

Here is another example to illustrate the difference between mandatory and discretionary dependencies:

Imagine you are managing a software development project to create a new application. One of the tasks on the project plan is to design the user interface (UI). Before the UI can be designed, you must complete the requirements gathering and analysis task. In this case, the requirements gathering and analysis task is a mandatory dependency for the UI design task, as the UI cannot be designed until the requirements have been gathered and analyzed.

Now, let's say you have also included a task on the project plan to conduct user testing on the application. The user testing task can be completed at any time. However, it should not impact the overall project time and schedule. In this case, the user testing task is a discretionary dependency, as it can be completed at any time, but it should not interfere with the other tasks on the project plan.

Which Type of Dependencies Are Inherent in the Nature of Work Being Performed on a Project?

The type of dependencies inherent like work being performed on a project are mandatory dependencies. These are also known as hard logic or hard dependencies. They are unavoidable and based on the fundamental nature of the work. For example, in construction, the foundation must be built before the walls can be erected.

Opposite of Dependency in Project Management

The opposite of dependency in project management is independence. An independent task or activity does not rely on any other task for its start or completion. It can be executed without waiting for other tasks to be finished.

What is a Dependency in Project Management?

Dependencies are relationships between tasks in project management where one task depends on the completion or initiation of another.

Here are 4 Types of Dependencies are

Mandatory Dependencies:

Based on the inherent nature of work (e.g., laws of physics).

Discretionary Dependencies:

Based on best practices or project preferences (soft logic).

External Dependencies:

Depend on external parties or events.

Internal Dependencies:

Involve relationships within the project team or tasks.

Final Thoughts

Understanding the key difference between mandatory and discretionary dependencies is crucial for effective project management.

Mandatory dependencies are non-negotiable and stem from the inherent nature of the project work, while discretionary dependencies are based on best practices and project manager's preferences. Recognizing these differences enables project managers to optimize schedules, manage risks, and ensure smoother project execution.

You can improve overall project outcomes and project planning by leveraging the characteristics of both dependencies.