In the world of process improvement, achieving success is only half the battle. The real challenge lies in maintaining those improvements over time. This is where the Control Phase of the Lean Six Sigma methodology becomes absolutely critical. At the heart of this phase lies the development of comprehensive process control documentation, which serves as the foundation for sustaining gains and preventing backsliding into old, inefficient habits.
Understanding the Control Phase in Lean Six Sigma
The Control Phase represents the final stage of the DMAIC (Define, Measure, Analyze, Improve, Control) methodology. After investing significant time and resources in identifying problems, analyzing root causes, and implementing solutions, organizations must ensure these improvements become permanent fixtures of their operational landscape. Process control documentation acts as the blueprint that guides teams in maintaining these enhanced processes long after the improvement project concludes. You might also enjoy reading about Process Owner Transition: How to Successfully Hand Off Your Improved Process.
Without proper documentation, even the most successful improvements can deteriorate within months. Studies have shown that up to 70% of process improvements fail to sustain themselves beyond one year without adequate control mechanisms. This sobering statistic underscores the vital importance of developing robust process control documentation. You might also enjoy reading about Before and After Comparison: How to Document Improvement Results Effectively.
Key Components of Process Control Documentation
Effective process control documentation encompasses several critical elements that work together to create a comprehensive system for maintaining improved processes.
Standard Operating Procedures (SOPs)
Standard Operating Procedures form the backbone of process control documentation. These detailed, step by step instructions outline exactly how each process should be performed. A well-written SOP removes ambiguity and ensures consistency regardless of who performs the task.
For example, consider a manufacturing company that improved its quality inspection process. Their SOP might include specific checkpoints, measurement techniques, and decision criteria. Rather than simply stating “inspect the product,” the SOP would detail: “Using calibrated digital calipers accurate to 0.01mm, measure the diameter at three points along the shaft: 25mm from the left end, center point, and 25mm from the right end. Record all three measurements. If any measurement falls outside the specification range of 15.00mm ± 0.05mm, mark the part as non-conforming and route to the rework station.”
Control Charts and Statistical Process Control Tools
Statistical Process Control (SPC) tools, particularly control charts, provide visual methods for monitoring process performance over time. These charts help teams distinguish between normal process variation and special cause variation that requires intervention.
Let us examine a practical example using sample data from a customer service call center that improved its average call handling time:
Sample Data Set: Daily Average Call Handling Time (in minutes)
Week 1: 8.2, 8.5, 8.3, 8.7, 8.4
Week 2: 8.6, 8.3, 8.4, 8.5, 8.7
Week 3: 8.4, 8.2, 8.6, 8.5, 8.3
Week 4: 8.5, 8.4, 8.3, 8.6, 8.4
The target average established during the Improve Phase was 8.5 minutes with control limits set at ±0.5 minutes (Upper Control Limit: 9.0 minutes, Lower Control Limit: 8.0 minutes). The control chart documentation would specify that any data point falling outside these limits triggers an investigation to identify and address the special cause variation.
Process Control Plans
A Process Control Plan serves as a comprehensive document that specifies what needs to be monitored, how frequently monitoring should occur, who is responsible for monitoring, and what actions should be taken when problems arise. This living document evolves with the process and provides clear accountability.
Consider a food processing facility that implemented improvements to reduce contamination risks. Their control plan would detail critical control points such as temperature monitoring (measured every 2 hours by line supervisors, with corrective action required if temperature exceeds 40°F), equipment sanitization schedules (documented on daily checklists by sanitation staff), and incoming material inspections (performed by quality technicians on every batch received).
Developing Effective Process Control Documentation
Engage the People Who Do the Work
One of the most common mistakes in developing process control documentation is creating it in isolation from the people who actually perform the work. The most effective documentation emerges from collaborative efforts that incorporate frontline worker insights and experience.
When operators, technicians, and staff members participate in documentation development, several benefits emerge. First, the documentation becomes more practical and grounded in reality rather than theoretical ideals. Second, the people who will use the documentation develop ownership and commitment to following it. Third, potential implementation barriers are identified and addressed before they become problems.
Make it Clear, Concise, and Accessible
Process control documentation must be written in language that users understand. Technical jargon should be minimized or clearly defined. Visual aids such as flowcharts, photographs, and diagrams enhance understanding and reduce the likelihood of misinterpretation.
Accessibility is equally important. Documentation stored in filing cabinets or buried deep in computer folders serves little practical purpose. Modern organizations increasingly use digital platforms that make documentation available at the point of use, whether through tablets on the production floor or mobile devices in the field.
Include Response Plans for Out-of-Control Situations
Comprehensive process control documentation anticipates problems and prescribes responses. When a process moves out of control, operators should not need to hunt for guidance or make decisions without clear direction.
For instance, if our call center example showed three consecutive days with average handling times exceeding 9.0 minutes, the response plan might specify: “1) Team leader reviews calls from the affected period to identify common issues, 2) Schedule refresher training if skill gaps are identified, 3) Notify IT department to check system performance, 4) Review staffing levels and schedule adjustments if volume exceeded capacity.”
Implementing and Maintaining Process Control Documentation
Training and Verification
Even the best documentation proves worthless if people do not know it exists or how to use it. Comprehensive training ensures all relevant personnel understand the new procedures and their role in maintaining process control. This training should include hands-on practice and verification that individuals can correctly apply the documented procedures.
Training documentation itself becomes part of the control system, with records showing who received training, when they were trained, and verification of their competency.
Regular Review and Updates
Process control documentation should never become static. As processes evolve, equipment changes, or better methods emerge, documentation must be updated to reflect current reality. Establishing a regular review schedule, such as quarterly or semi-annually, ensures documentation remains relevant and accurate.
Version control becomes critical in this context. Each document should clearly indicate its revision level, date of last update, and approval authority. This prevents confusion about which version represents the current standard.
Audit and Compliance Checking
Regular audits verify that documented procedures are being followed in practice. These audits should be viewed as learning opportunities rather than punitive exercises. When gaps between documentation and practice emerge, organizations must determine whether the documentation needs revision or whether additional training and reinforcement are required.
Real World Impact: A Case Study
A mid-sized electronics manufacturer implemented Lean Six Sigma improvements that reduced defect rates from 4.2% to 1.1% over six months. Initially celebrating this success, the company watched defect rates creep back to 3.1% within eight months as team members gradually reverted to familiar patterns and new employees received inconsistent training.
Recognizing the problem, the organization invested in comprehensive process control documentation including detailed SOPs, control charts updated daily, and a structured training program. One year later, defect rates stabilized at 0.9%, demonstrating that proper documentation and control systems not only sustained improvements but enabled further gains.
The Path Forward
Developing process control documentation requires time, effort, and expertise, but the return on investment proves substantial. Organizations that master this critical element of the Control Phase transform temporary improvements into permanent competitive advantages. They build capabilities that compound over time as each successive improvement adds to a growing foundation of documented, controlled, and optimized processes.
The journey to process excellence demands more than good intentions. It requires systematic approaches, proven methodologies, and the knowledge to implement them effectively. The skills needed to develop robust process control documentation and successfully navigate the Control Phase are precisely what comprehensive Lean Six Sigma training provides.
Take Control of Your Process Improvement Journey
Understanding the importance of process control documentation is the first step. Developing the expertise to create and implement these systems is the next. Whether you are looking to enhance your professional capabilities or transform your organization’s operational excellence, Lean Six Sigma training provides the framework, tools, and techniques you need to succeed.
Enrol in Lean Six Sigma Training Today and gain the skills to not only improve processes but to make those improvements last. Learn from experienced practitioners who understand the real world challenges of sustaining change. Master the tools and techniques that separate temporary fixes from permanent solutions. Join thousands of professionals who have transformed their careers and organizations through proven process improvement methodologies. Your journey to sustainable excellence begins with a single decision. Make that decision today and invest in training that delivers lasting value.
