Phase Six Sigma is a misstatement. The correct term is "Define phase of Six Sigma," the first step in the DMAIC methodology used to identify problems, set goals, and define project scope. This phase ensures teams focus on the right issues with clear objectives.
The Define phase sets the foundation for all subsequent work. It clarifies what success looks like, who is affected, and what resources are needed. Without a solid Define phase, teams risk solving the wrong problem or wasting time on low-impact changes.
According to the American Society for Quality (ASQ), 70% of Six Sigma projects fail due to poor problem definition. A well-executed Define phase prevents this by aligning stakeholders, establishing metrics, and setting measurable targets early.
Teams begin by identifying a business problem that impacts customer satisfaction, cost, or cycle time. For example, a hospital's emergency department reports patient wait times exceeding 90 minutes. The team defines the issue as "reducing average ER wait time from 90 to 45 minutes within six months."
Next, they map the current process using tools like SIPOC (Suppliers, Inputs, Process, Outputs, Customers). This visual model shows all elements involved and reveals gaps or inefficiencies. In the hospital example, the SIPOC revealed that triage nurses lacked access to real-time bed availability data.
Finally, teams create a project charter-a formal document outlining the problem statement, goal, scope, timeline, budget, and team roles. The charter must include a metric for success. In the hospital case, the metric was "reduce average ER wait time from 90 to 45 minutes."
The Define phase relies on structured inputs and tools to avoid assumptions. Core components include:
One non-obvious requirement is defining the "voice of the customer" (VOC). This involves gathering direct feedback from users to understand their pain points. A retail bank launching a mobile app used VOC data from 1,200 customer surveys to discover that 68% struggled with resetting passwords. This insight shaped the project's focus.
Another critical tool is the Pareto chart, which ranks problems by frequency or impact. In a manufacturing plant, engineers used it to show that 80% of machine downtime came from just three root causes. This helped prioritize efforts during the Define phase.
Many teams skip defining the problem, assuming everyone agrees on the issue. This leads to wasted effort. For example, a software company launched a project to "improve user engagement" without specifying which feature or behavior to target. The result: no measurable outcome and a failed initiative.
Another mistake is conflating symptoms with root causes. A call center reported high abandonment rates. The team assumed agents were untrained. But the Define phase revealed that the real issue was a broken IVR system routing calls incorrectly. Fixing training wouldn't have solved the actual problem.
A lesser-known pitfall is failing to secure executive sponsorship early. Without buy-in from leadership, teams struggle to access data, staff, or budget. ASQ notes that projects with visible executive support are 3.4 times more likely to succeed.
A regional health system aimed to reduce 30-day readmission rates for heart failure patients. The Define phase began with a review of 1,800 patient records. They found that 42% of readmissions occurred because patients didn't understand discharge instructions.
Using a SIPOC diagram, the team mapped the discharge process. They identified gaps: no standardized handout, inconsistent verbal explanations, and no follow-up call within 48 hours. The problem statement became: "Reduce 30-day readmission rate for heart failure patients from 22% to 12% within 12 months."
The project charter included a goal of increasing patient comprehension from 57% to 85%, measured via post-discharge surveys. The team secured approval from the chief medical officer and assigned a nurse manager to lead the project. This clarity ensured alignment and accountability.
The Define phase is the first of five stages in the DMAIC process: Define, Measure, Analyze, Improve, Control. Each phase builds on the last. Skipping or rushing through Define undermines all later steps.
After Define, teams move to Measure-collecting baseline data to quantify the problem. In the hospital example, they tracked wait times daily for four weeks to establish a 90-minute average. Only then could they assess whether changes had an effect.
For context, Six Sigma aims to reduce defects to 3.4 per million opportunities. The Define phase ensures the project targets a meaningful opportunity. As Motorola's original Six Sigma documentation states, "Without a clear definition, there is no standard against which to measure progress."
| Phase | Primary Goal | Key Output |
|---|---|---|
| Define | Clarify problem and scope | Project charter, SIPOC, problem statement |
| Measure | Quantify current performance | Data collection plan, baseline metrics |
| Analyze | Find root causes | Root cause analysis report |
| Improve | Test and implement solutions | Improved process design, pilot results |
| Control | Sustain gains | Standard operating procedures, monitoring plan |
I once led a Six Sigma project to reduce invoice processing errors in a logistics firm. We started with a vague goal: "fix billing issues." After conducting interviews and reviewing 120 error reports, we realized the real problem was inconsistent data entry across three departments. The Define phase forced us to narrow the scope to "reduce incorrect invoice entries from 14% to 3% within nine months." That precision made all the difference.
Understanding the Define phase is essential to applying Six Sigma effectively. It's not just about starting a project-it's about starting it right. Without a clear definition, even the most advanced analysis tools cannot deliver results.