← All guides

Six Sigma Project Timeline and Milestones Gantt Chart

Six Sigma DMAIC projects follow a defined phase structure with tollgates at each transition. Here's the Gantt chart template that maps every phase and milestone.

Six Sigma Project Timeline and Milestones Gantt Chart

The Problem: Six Sigma Projects Drag or Skip to Solutions Too Early

Six Sigma DMAIC projects fail in two predictable ways. The first is timeline drag: the project stays in Measure or Analyze for months while the team collects data, debates root causes, and defers to more analysis. The project loses momentum, team members get reassigned, and the improvement never lands.

The second failure mode is jumping to solutions. The team identifies a plausible root cause in week 3 and skips to Improve before the data supports the conclusion. The solution is implemented, the problem returns, and the project is closed with a "success" that reverses itself within 60 days.

A Six Sigma project Gantt chart sets time boundaries on each phase that are tight enough to maintain momentum but long enough to do the analytical work correctly. Tollgate reviews at each phase transition force the team to demonstrate they've completed the phase before moving forward. gantt-chart.io gives your project team and sponsors a shared timeline where every phase boundary is visible and every tollgate is a scheduled decision point.

Prerequisites

  • Project charter approved: problem statement, goal statement, scope, team, and timeline
  • Sponsor confirmed with authority to approve resources and remove barriers
  • Belt level assigned: who is leading — Black Belt, Green Belt, or Master Black Belt coach?
  • Baseline data available or a plan to collect it
  • Process owner identified: who owns the process being improved and will sustain the changes?
  • Team assembled: 3–5 core team members with process knowledge and capacity to participate

Six Sigma DMAIC Gantt Chart Template

Phase 1: Define (Weeks 1–3)

  • [ ] Project charter completed and approved by sponsor and process owner
  • [ ] Problem statement written: specific, measurable, time-bound — no cause or solution embedded
  • [ ] Goal statement written: what improvement, by how much, by when?
  • [ ] SIPOC diagram completed: suppliers, inputs, process, outputs, customers
  • [ ] Voice of customer collected: what does the customer require from this process?
  • [ ] Define tollgate: sponsor approves charter, team, scope, and timeline before Measure begins

Phase 2: Measure (Weeks 3–7)

  • [ ] Process map developed at the task level for the process in scope
  • [ ] Key process input variables (KPIVs) and key process output variables (KPOVs) identified
  • [ ] Measurement system analysis (MSA/Gage R&R) completed for primary output metric
  • [ ] Baseline data collected: minimum 30 data points for initial capability analysis
  • [ ] Current process capability calculated: Cp, Cpk, or DPMO as appropriate
  • [ ] Measure tollgate: team presents data collection plan, baseline capability, and MSA results

Phase 3: Analyze (Weeks 6–11)

  • [ ] Fishbone (Ishikawa) or affinity diagram used to generate potential root cause hypotheses
  • [ ] Data analysis conducted: Pareto, regression, hypothesis testing, or designed experiments
  • [ ] Root causes validated with data — not just subject matter expert opinion
  • [ ] Vital few root causes identified: what accounts for 80%+ of the defect or variation?
  • [ ] Root cause confirmation: statistical evidence supports each identified root cause
  • [ ] Analyze tollgate: team demonstrates data-driven root cause identification to sponsor

Phase 4: Improve (Weeks 10–16)

  • [ ] Solution brainstorming: multiple solutions considered for each validated root cause
  • [ ] Solution evaluation: effort vs. impact matrix used to prioritize solutions
  • [ ] Pilot solution designed: controlled test of proposed solution in limited scope
  • [ ] Pilot conducted with measurement: does the solution produce the expected improvement?
  • [ ] Pilot results analyzed: confirm improvement vs. baseline with statistical confidence
  • [ ] Improve tollgate: sponsor approves full-scale implementation based on pilot results

Phase 5: Control (Weeks 14–18)

  • [ ] Control plan developed: what is monitored, at what frequency, by whom, with what response
  • [ ] Control charts implemented: SPC charts set up for critical output metrics
  • [ ] Updated SOPs and work instructions reflect new process
  • [ ] Process owner and operators trained on new process and control plan
  • [ ] Control phase data collected: verify improvement is holding over time
  • [ ] Control tollgate: final project review — improvement sustained, process owner accepts handoff

Phase 6: Project Close-Out (Weeks 17–20)

  • [ ] Financial benefits calculated and validated by finance — savings documented with methodology
  • [ ] Project storyboard or report completed: full DMAIC story with data, results, and lessons
  • [ ] Lessons learned documented: what would the team do differently?
  • [ ] Replication opportunities identified: where else in the organization does this root cause exist?
  • [ ] Recognition: team contributions acknowledged formally
  • [ ] Project closed in project management system with final benefit figure confirmed

Common Mistakes

1. Skipping MSA in Measure. If the measurement system can't reliably detect the defect or measure the output variable, all the data collected is noise. MSA is not optional for projects with measurement uncertainty.

2. Root causes identified without data. The most common team meeting produces a fishbone diagram full of suspected causes, a quick vote on the most likely, and a jump to solutions. This is brainstorming, not root cause analysis. Every cause requires data validation.

3. Pilot bypassed. Implementing a solution across the full process without a pilot multiplies the blast radius of an ineffective solution. A 2-week pilot with measurement is not optional.

4. Control plan without an owner. A control plan that says "quality checks the output" without naming the specific person and frequency is not a control plan. Every row needs a name, a frequency, and a defined response to an out-of-control condition.

5. Benefits claimed before control phase confirms sustainability. Financial benefits should be confirmed after the Control phase demonstrates the improvement is sustained — not at the end of the Improve phase when the pilot looks good but full-scale implementation hasn't been tested.

Quick-Start in gantt-chart.io

  1. Open gantt-chart.io and create a project called "Six Sigma — [Project Name]"
  2. Add the six DMAIC phases plus close-out, each as a parent row with sub-tasks
  3. Add tollgate milestones at the end of each phase — these are sponsor decision points, not just checkboxes
  4. Assign the Belt (Black Belt or Green Belt) as project owner; assign the sponsor to tollgate reviews
  5. Set the financial validation in close-out as the final milestone before project is officially closed

FAQ

How long should a Six Sigma project take?

4–6 months for a well-scoped project. Projects that run longer than 6 months usually have scope that's too broad or an Analyze phase that's searching for data instead of using the data it has.

What's a tollgate and who runs it?

A tollgate is a formal review at the end of each DMAIC phase where the team presents their work to the sponsor. The sponsor approves progression to the next phase or sends the team back to complete the current phase. It is the sponsor's meeting, not the team's.

How do we scope a Six Sigma project correctly?

The project should be solvable within 4–6 months by a part-time team. If you can't define a specific, measurable output metric that you're trying to move, the scope is too broad. "Improve quality" is not a Six Sigma project; "Reduce customer returns from 4.2% to below 2.0% in the Memphis facility" is.

When is Six Sigma the right tool?

When the root cause of a problem is unknown and requires data analysis to identify. If the root cause is already known, use a simple implementation project. If the problem is a waste or flow issue, lean tools are often faster and more appropriate.

What's the minimum team size for a Six Sigma project?

3 people: the Belt leading the project, a process expert who knows how the work actually gets done, and the process owner who will sustain the improvement. Larger teams (5–7) are appropriate for complex cross-functional processes.

Six Sigma delivers durable improvements when every phase is completed with discipline — and when tollgates enforce the completion standard before the next phase begins. Build your DMAIC project timeline in gantt-chart.io, schedule tollgates as hard milestones with your sponsor, and don't implement solutions before pilot data confirms they work.