Organizations invest significant resources in Lean Six Sigma initiatives, expecting sustainable improvements and measurable results. However, many projects that show initial promise ultimately fail to deliver long-term value. The primary culprit? Critical mistakes made during the Control Phase that allow hard-won gains to slip away. Understanding these common pitfalls is essential for any organization committed to continuous improvement and operational excellence.
Understanding the Control Phase in Six Sigma
The Control Phase represents the final and arguably most important stage of the DMAIC (Define, Measure, Analyze, Improve, Control) methodology. After teams have worked diligently to recognize phase transitions throughout their project and implement improvements, the Control Phase ensures that these gains become permanent fixtures within organizational processes. This phase transforms temporary victories into sustained competitive advantages. You might also enjoy reading about Response Plan Development: What to Do When Your Process Goes Out of Control.
Despite its critical importance, the Control Phase often receives less attention and resources than earlier project stages. This neglect creates a dangerous vulnerability where improvements deteriorate over time, returning processes to their original problematic states. When organizations fail to properly execute the Control Phase, they essentially waste all previous investment in the project. You might also enjoy reading about Process Owner Transition: How to Successfully Hand Off Your Improved Process.
The Most Common Control Phase Mistakes
1. Inadequate Documentation of New Processes
One of the most prevalent mistakes occurs when teams fail to create comprehensive documentation for their improved processes. After months of analysis and implementation, team members may assume that everyone understands the new procedures. This assumption proves disastrous when key personnel leave, new employees join, or memories fade over time. You might also enjoy reading about Documentation Standards for Control Phase: Essential Records to Maintain in Lean Six Sigma Projects.
Effective process documentation should include detailed standard operating procedures, visual work instructions, and clear explanations of why changes were made. This documentation serves as the institutional memory that preserves improvements regardless of staff turnover or organizational changes. Without it, processes naturally drift back toward previous inefficient methods.
2. Failure to Establish Meaningful Control Charts
Control charts represent the cornerstone of statistical process control within Lean Six Sigma methodologies. However, many organizations either skip this critical tool entirely or implement it incorrectly. Some teams create overly complex charts that no one understands or maintains, while others develop simplistic tracking mechanisms that fail to detect meaningful process variations.
The key lies in developing control charts that are both statistically valid and practically useful for frontline workers. These charts must be reviewed regularly, with clear protocols for responding when data points fall outside control limits. When control charts become decorative rather than functional, they cannot fulfill their protective purpose.
3. Insufficient Training for Process Owners
As Six Sigma project teams disband and return to their regular duties, ongoing responsibility for improved processes transfers to designated process owners. Unfortunately, many organizations fail to adequately prepare these individuals for their critical role. Process owners need more than surface-level understanding; they require deep knowledge of why improvements were made, how to monitor them effectively, and when to sound alarms about deterioration.
Comprehensive training programs should cover the technical aspects of the improved process, the statistical tools used for monitoring, and the decision-making authority granted to process owners. Without this preparation, even well-intentioned owners cannot recognize phase changes or variations that signal problems, allowing processes to degrade unnoticed.
4. Lack of Response Plans for Out-of-Control Situations
Identifying that a process has drifted out of control represents only half the battle. Organizations must establish clear response plans that specify exactly what actions to take when problems arise. Many teams celebrate their improvements and move on without creating these essential contingency protocols.
Effective response plans detail who should be notified when issues occur, what immediate actions should be taken, and how to escalate problems that cannot be quickly resolved. These plans prevent the paralysis that often occurs when unexpected problems arise, enabling rapid corrective action that protects improvement gains.
5. Neglecting to Integrate Changes into Management Systems
For improvements to truly stick, they must become embedded within existing management systems and organizational infrastructure. This integration includes updating quality management system documentation, revising performance metrics, adjusting compensation or recognition systems, and modifying audit checklists to verify compliance with new procedures.
When improvements exist outside formal management systems, they remain vulnerable to being overlooked, bypassed, or forgotten during times of stress or organizational change. Integration transforms improvements from special projects into standard business practices that receive ongoing attention and resources.
The Hidden Dangers of Premature Project Closure
Many organizations, eager to declare victory and redeploy resources to new initiatives, close Lean Six Sigma projects before the Control Phase has been properly established. This premature closure often occurs when financial pressures mount or when leadership loses patience with longer project timelines.
However, closing projects before control mechanisms have been tested and proven sustainable virtually guarantees failure. Best practices suggest monitoring improved processes for at least 30 to 90 days before project closure, depending on process cycle times and complexity. This patience ensures that control systems actually work and that unexpected issues can be addressed while the project team remains engaged.
Cultural and Organizational Factors That Undermine Control
Beyond technical mistakes, organizational culture plays a significant role in Control Phase success or failure. Companies that celebrate the completion of improvement projects without equally recognizing the importance of sustaining those improvements send problematic messages. When recognition and rewards focus exclusively on implementing changes rather than maintaining them, employees naturally prioritize new initiatives over protecting existing gains.
Additionally, organizations that fail to hold leaders accountable for sustaining improvements create environments where the Control Phase receives insufficient attention and resources. Effective control requires ongoing investment, and leadership must demonstrate commitment through resource allocation, regular reviews, and consequences when improvements are allowed to deteriorate.
Best Practices for Control Phase Success
Create a Formal Control Plan
Every Six Sigma project should conclude with a comprehensive control plan that specifies what will be monitored, how frequently, by whom, and with what tools. This document serves as the blueprint for sustaining improvements and should be reviewed and updated regularly as conditions change.
Implement Layered Process Audits
Layered process audits involve multiple levels of management conducting brief, frequent checks on critical process elements. This approach ensures that improvements receive ongoing attention from leadership while catching problems early before they become serious.
Establish Regular Review Cycles
Process owners and management should conduct structured reviews of controlled processes at predetermined intervals. These reviews examine control chart data, assess compliance with new procedures, and identify emerging issues that require attention.
Maintain Project Team Involvement
Rather than completely disbanding project teams immediately after implementation, organizations should maintain some level of team involvement during the initial control period. This extended engagement allows for rapid problem-solving if unexpected issues arise and reinforces the importance of sustaining improvements.
Conclusion
The Control Phase represents the difference between temporary improvement projects and lasting organizational transformation. By understanding and avoiding common mistakes such as inadequate documentation, poor control chart implementation, insufficient training, absent response plans, and premature project closure, organizations can protect their Lean Six Sigma investments and realize sustained benefits.
Success requires commitment from all organizational levels to recognize phase transitions, maintain vigilance, and dedicate resources to preserving improvements. When companies treat the Control Phase with the same seriousness as earlier DMAIC stages, they transform Six Sigma from a series of isolated projects into a genuine competitive advantage built on operational excellence. The question is not whether you can afford to properly execute the Control Phase, but whether you can afford not to.
