The Define Phase represents the crucial foundation of any Lean Six Sigma project, setting the stage for success or failure before actual improvement work begins. Within this phase, identifying project constraints and assumptions stands as one of the most critical yet often overlooked activities. Understanding these elements helps project teams navigate realistic boundaries while challenging potentially limiting beliefs that could hinder innovation and process improvement.
Understanding the Define Phase Context
Before diving into constraints and assumptions, it is essential to understand where these elements fit within the broader Define Phase. This initial stage of the DMAIC (Define, Measure, Analyze, Improve, Control) methodology establishes the project’s foundation by clarifying the problem, setting objectives, and determining the scope. Within this framework, constraints and assumptions serve as guardrails and hypotheses that shape how the team approaches problem-solving. You might also enjoy reading about Stakeholder Analysis in Six Sigma: A Complete Guide to Identifying and Managing Key Players.
The Define Phase typically produces several key deliverables including the project charter, SIPOC diagram, and stakeholder analysis. Identifying constraints and assumptions feeds directly into these deliverables, ensuring that everyone involved maintains realistic expectations while staying open to breakthrough improvements. You might also enjoy reading about Define Phase Documentation: What to Record and How to Organize It for Project Success.
What Are Project Constraints?
Project constraints represent the fixed boundaries within which your Lean Six Sigma initiative must operate. These limitations are typically non-negotiable factors that shape what solutions are feasible and how the team can proceed. Understanding constraints early prevents wasted effort on solutions that cannot be implemented within the organizational reality.
Common Types of Project Constraints
Time Constraints: Every improvement project operates within temporal boundaries. A manufacturing company might need to complete a production line improvement before the peak season begins in three months. For example, a beverage company facing summer demand would have a hard deadline for completing packaging line improvements by April to avoid missing their highest revenue period.
Budget Constraints: Financial limitations determine what resources, tools, and personnel can be allocated to the project. A healthcare clinic looking to reduce patient wait times might have only $25,000 available for process improvements, ruling out certain technology solutions but keeping staffing optimization and workflow redesign options open.
Resource Constraints: Human capital, equipment, technology, and facilities represent finite resources. A customer service department might have only two team members available to dedicate 20% of their time to improvement activities, limiting how quickly data can be collected and analyzed.
Regulatory and Compliance Constraints: Certain industries operate under strict regulatory frameworks that cannot be violated. A pharmaceutical company working to reduce batch processing time must still comply with FDA validation requirements, regardless of potential efficiency gains from shortcutting documentation procedures.
Technical Constraints: Existing infrastructure and technology capabilities impose real limitations. A distribution center using a warehouse management system from 2010 might be constrained by the system’s inability to support real-time inventory tracking, requiring workarounds or significant investment in upgrades.
Real-World Constraint Example
Consider a retail bank aiming to reduce mortgage application processing time from 45 days to 30 days. Their constraints might include:
- Time: Project must complete within six months to align with the fiscal year planning cycle
- Budget: Maximum expenditure of $150,000 for process improvements
- Resources: Three loan officers available for 10 hours per week, one process improvement specialist full-time
- Regulatory: Must maintain compliance with Truth in Lending Act and undergo third-party audits
- Technical: Current loan origination software cannot be replaced, only configured differently
These constraints immediately inform the team that they cannot pursue solutions requiring new software platforms, cannot hire additional permanent staff, and must work within existing regulatory frameworks. However, they can explore workflow optimization, automation of specific tasks within the current system, and improved handoffs between departments.
What Are Project Assumptions?
While constraints represent known limitations, assumptions are beliefs or hypotheses about conditions that the team accepts as true for planning purposes but have not been verified. Assumptions carry inherent risk because if they prove false, the entire project direction might need adjustment. Successful Lean Six Sigma practitioners explicitly identify and document assumptions, then validate or challenge them during the Measure and Analyze phases.
Categories of Common Assumptions
Stakeholder Assumptions: Teams often assume stakeholder support will remain consistent throughout the project. For instance, assuming that department managers will continue supporting the initiative even when it requires their staff to change long-standing work habits.
Data Assumptions: Projects frequently assume that necessary data exists, is accurate, and can be accessed. A supply chain improvement project might assume that supplier delivery performance data has been consistently recorded, only to discover significant gaps or inconsistencies later.
Process Assumptions: Teams may assume they understand how current processes actually function based on standard operating procedures, when reality often diverges significantly from documentation. The assumption that employees follow documented procedures exactly as written rarely holds true in practice.
Resource Assumptions: Assuming that promised resources will remain available throughout the project duration represents a common risk. Subject matter experts might be reassigned, budgets frozen, or equipment taken offline for unrelated reasons.
Outcome Assumptions: Many projects assume that identified improvements will be adopted by end users without significant resistance. The assumption that providing a better process automatically leads to behavioral change overlooks the human dimensions of organizational change.
Sample Assumptions from a Hospital Emergency Department Project
A hospital aiming to reduce emergency department wait times from 120 minutes to 75 minutes might document these assumptions:
- Physicians and nurses will accurately record timestamps for patient encounters in the electronic health record system
- Current staffing levels are adequate, and the problem stems from workflow inefficiencies rather than understaffing
- Patients presenting during peak hours have similar acuity levels to those arriving during off-peak times
- The laboratory can maintain current turnaround times for stat orders without becoming a bottleneck
- Administration will support process changes even if they require upfront investments in training
Each of these assumptions requires validation. The team would need to audit timestamp accuracy, analyze acuity data by time of day, assess laboratory capacity, and secure explicit administrative commitment in writing.
The Critical Distinction Between Constraints and Assumptions
Distinguishing between constraints and assumptions proves vital for project success. Constraints are accepted as fixed, while assumptions should be challenged and validated. Mistaking an assumption for a constraint can unnecessarily limit solution options, while treating a real constraint as a mere assumption wastes resources pursuing impossible solutions.
For example, a manufacturing team might assume they cannot modify a particular machine because it was expensive and recently installed. However, upon investigation, they discover the machine settings can be adjusted without voiding the warranty. What they treated as a constraint was actually an untested assumption. Conversely, assuming they have flexibility in safety procedures when regulatory constraints exist could lead to compliance violations.
Documenting Constraints and Assumptions
Professional project management requires formal documentation of both constraints and assumptions, typically within the project charter. This documentation should include:
- Clear statement of each constraint or assumption
- Source or reason for the constraint
- Impact on project scope and approach
- Validation method for assumptions
- Risk level if an assumption proves false
- Contingency plans for high-risk assumptions
Creating a simple matrix helps teams track these elements systematically throughout the project lifecycle, updating status as assumptions are validated or invalidated.
Practical Strategies for Identifying Constraints and Assumptions
Conduct Stakeholder Interviews: Meeting with project sponsors, process owners, and subject matter experts surfaces constraints that might not be obvious from documentation alone. Ask explicitly about limitations, sacred cows, and untouchable elements of the current system.
Review Historical Projects: Examining past improvement initiatives reveals patterns of constraints and commonly held assumptions. Learning from previous experiences prevents repeated mistakes and identifies persistent organizational limitations.
Challenge Everything: Adopt a mindset of respectful skepticism. When someone states a limitation, ask whether it represents a true constraint or an assumption based on past practice. The question “What would need to be true for this to change?” often reveals flexibility where none seemed to exist.
Involve Frontline Workers: Employees who perform the work daily often know constraints and realities that management overlooks. Their practical knowledge helps distinguish between theoretical procedures and actual operational limitations.
The Path Forward
Successfully identifying and managing project constraints and assumptions during the Define Phase sets the trajectory for the entire Lean Six Sigma initiative. Teams that invest time in this foundational work avoid false starts, manage stakeholder expectations effectively, and focus improvement efforts where they can genuinely create value. The discipline required to distinguish fixed constraints from testable assumptions separates mediocre process improvement from transformational organizational change.
Mastering these skills does not happen through reading alone. Practical application under the guidance of experienced professionals accelerates learning and builds the confidence needed to lead successful improvement projects.
Enrol in Lean Six Sigma Training Today
Understanding the theory behind identifying constraints and assumptions provides a starting point, but true competency develops through structured training and hands-on practice. Professional Lean Six Sigma training programs provide the frameworks, tools, and mentorship necessary to excel in the Define Phase and throughout the entire DMAIC methodology.
Whether you are pursuing Yellow Belt, Green Belt, or Black Belt certification, comprehensive training equips you with the skills employers value and projects demand. You will learn to navigate complex organizational dynamics, challenge assumptions constructively, and work effectively within real-world constraints to deliver measurable results.
Do not let another improvement opportunity pass because of unclear project boundaries or untested assumptions. Enrol in Lean Six Sigma training today and gain the expertise to lead projects that transform operations, reduce waste, and create lasting value. Your journey toward process excellence begins with proper preparation in the Define Phase, and professional training provides the foundation for a successful career in continuous improvement.
Take the first step toward certification and join thousands of professionals who have elevated their careers through Lean Six Sigma expertise. The knowledge and skills you gain will serve you throughout your professional life, opening doors to leadership opportunities and empowering you to make meaningful contributions to organizational success.
