Most projects begin with some level of uncertainty, which means they rely on assumptions. An assumption is something you believe will be true in the future.

Some assumptions must be made on projects when there is a lack of information available to predict the future accurately. If project managers had to wait for absolute certainty, most projects would never get off the starting block within organizations!

Experienced project managers focus on improving how they identify, document, and reduce assumptions wherever possible.

Documenting Assumptions in Project Management

During project planning and execution, some facts and issues are known while others must be estimated. Project managers can’t just hope they will have the necessary resources to complete a project successfully.

For example, if the required resources are not available, then key project milestones may be missed and the project may fall short of its goals.

To avoid this, project managers have to manage and mitigate using informed assumptions and constraints. These assumptions often relate to:

• Project Scope
• Project Budget
• Business Sponsorship
• Requirements
• Resources
• Customers
• Technology
• Expectations
• Third Parties
• Other Assumptions

 

These assumptions should be clearly communicated to project stakeholders and included in the project assumption log.

Assumptions in Projects

Assumptions apply at all stages of the project lifecycle and are typically documented at the beginning. But they are usually forgotten as the project progresses.

Because assumptions might turn out to be false, they add risk to your project. They can affect any part of the plan, including how the final solution is implemented.

It’s important to document each assumption and note any actions required if they don’t hold true. Revisit assumptions during the project to help the project team stay within scope, time, and budget.

An Assumption is Not a Constraint

Assumptions are forecasts about what may happen in the future. Constraints, on the other hand, are limits on freedom of choice. Constraints can have a negative effect on the project and are not often under the control of a project manager.

A common example is a business constraint, which limits the project based on the current organizational environment. When determining assumptions, it may be important to consider any project-related constraints as they can lead to new assumptions.

Constraints must be clearly identified and built into the plan to keep the project management plan realistic.

Typical Constraints  in Projects

Most project constraints fall under three key areas: project timeline, cost, and resources. Project managers need to list any major limitations impacting a project:

• Schedule – Estimated tasks and events needed to complete the project, organized into a structured sequence to meet a specified project end date.
• Budget – The estimated cost of the project, allocated to tasks, resources, and phases as needed to complete the project.
• Resources – The estimated staff resources needed to complete the project, according to number, type, work hours, and skills.
• Skill levels – The capability of assigned personnel to complete tasks effectively.
• Legal – Compliance with laws and regulations that apply to the project.
• Procurement – The anticipated performance of contractors, vendors, and suppliers to deliver goods and services according to contracts and project requirements.
• Dependencies – Tasks or deliverables that rely on input from other teams or projects.
• Policies – Internal rules or processes that must be followed.
• Technology – Limitations or requirements based on tools and systems used.
• Other Constraints – Any additional constraints that might affect project success.

 

Project Dependencies and Assumptions

Dependencies are deliverables from other projects that your project needs in order to launch. When overlooked, they can cause project teams to miss their milestones and target dates.

It’s important to determine a link between project assumptions and constraints, and then identify any dependencies between them. Project managers need to document and communicate the dependencies for inclusion in the project plan.

Project Risks and Assumptions

An assumption is something a project manager expects to happen. A risk, on the other hand, is something that may happen and could negatively affect the project.

If the assumption turns out to be true, the project stays on track. If the risk happens, it can cause delays or other issues.

The Assumption Management Process

Assumptions don’t stay static. As your project moves forward, they need to be reviewed, adjusted, or removed. This process keeps your plan realistic and helps avoid surprises. Here’s how to manage assumptions:

1. Identify and Challenge

The first step in the assumption management process is identification. Listen for phrases like “I think” in meetings—they often signal an assumption. Check the confidence level of the project team members in completing the project. If hesitation is clear, dig deeper.

Ask the following:

• What were the original assumptions?
• Have new ones emerged?
• If any assumption proves to be false, what will be the consequences?

 

Challenge all assumptions and constraints. Then record all assumptions in one place.

2. Assess

Each assumption must be viewed with an appropriate degree of skepticism. Quantify the assumptions as much as possible in order to determine their potential impact on the project.

Assumptions should be evaluated according to the confidence level. Ask: “If this assumption is wrong, how will it affect the project?”

3. Incorporate

Once assumptions are identified and assessed, add them to the project plan. Align them with the planned tasks, project schedule, budget, and required resources. These inputs, along with confirmed facts, shape a realistic and actionable plan.

4. Control

Monitor assumptions throughout the project. Avoid treating them as facts without review. It is necessary to track assumptions to assess their impact on the project and to develop contingency plans should they prove to be invalid.

Schedule regular check-ins with the project team to update or remove assumptions that no longer apply. In these reviews, the project manager should ensure that follow-up actions are assigned and completed. A project manager can use the Risk Management Process to manage assumptions.

5. Review

At the end of the project, revisit all assumptions. Evaluate how they were identified, assessed, and managed. This review improves future assumption handling and supports long-term project success.

Best Practices For Assumption Management

Effective assumption management helps reduce potential risk and supports better decision-making throughout the project lifecycle. Here are the best practices to keep your project on track:

1. Make Assumptions Clear and Fact-Based

Assumptions need to be specific, manageable, and based on the best available information at the time that the assumption is made. As more data becomes available, update and refine them to improve accuracy.

2. Monitor Assumptions Throughout the Project

Assumptions need to be monitored and managed on an ongoing basis throughout the project lifecycle in order to review and test any assumptions.

3. Align Assumption Management with Risk Management

Assumption management is directly tied to managing risks because they both relate to unknowns. Review key assumptions whenever you update the risk log to stay proactive and reduce surprises.

4. Use the Risk Log to Manage Assumptions

Include assumptions in the Risk Log and review them during regular risk meetings. The Risk Log provides a standard means for recording assumptions and how they were derived:

• Determining the ownership of the assumptions.
• Evaluating the stability of and the impact on the project if any of the assumptions prove to be true or false.
• Defining the actions necessary to progress and monitor the assumptions.
• Making provisions for conflicting assumptions.
• Scheduling when assumptions are to be validated and reviewed throughout the life of the project.
• After a project ends, assumptions may need to be reviewed as they could negatively impact the realization of post-project benefits.

 

The Danger with Assumptions

The key danger specific to assumptions is that they become accepted wisdom. As project changes occur, you may not know the exact impact of the change on the project. This is why assumptions must be managed throughout the project life cycle.

Keeping Assumptions in Check with BrightWork 365

Assumptions are a natural part of project planning, but they must be tracked, tested, and updated to avoid risks that could derail progress.

When handled correctly, assumption management supports better decision-making and contributes to overall project success.

BrightWork 365 makes it easy to manage project assumptions, risks, and tasks in one collaborative platform. Plan smarter, deliver better.