Six Sigma — Cheatsheets

DMAIC phases

Phase	Purpose	Key tools

|---|---|---|

Define	Define problem, goals, customer requirements	Project Charter, SIPOC
Measure	Establish current process performance (data-based)	Operational definitions, data collection plan, process capability
Analyze	Identify root causes using Measure's data	Fishbone/Ishikawa diagram, 5 Whys
Improve	Develop, test, implement solutions	Pilot testing before full rollout
Control	Sustain improvement over time	Control charts, Control Plan

Concept	Value

|---|---|

Six Sigma quality	≤3.4 defects per million opportunities
Statistical basis	Specification limits 6 standard deviations from process mean

(needs verification — recheck against current source: exact figures are standard reference points but can vary slightly by source/convention.)

Belt	Role

|---|---|

Yellow Belt	Basic awareness, team member support
Green Belt	Leads smaller projects, applies DMAIC
Black Belt	Leads complex projects, deeper statistics, mentors Green Belts
Master Black Belt	Organization-wide strategy, Black Belt mentorship

(needs verification — recheck against current source: responsibilities vary by certifying body — ASQ, IASSC, etc.)

Type	Source	Response

|---|---|---|

Common cause	Natural, inherent, always-present factors	Redesign the process
Special cause	Identifiable, specific, often intermittent	Find and eliminate the source

Technique	Purpose

|---|---|

Hypothesis testing	Test if observed difference is statistically significant
Design of Experiments (DOE)	Efficiently test multiple variables, detect interaction effects
Regression analysis	Model relationship between inputs and outputs

Framework	Core question

|---|---|

Six Sigma	How much does this process vary, and why?
Lean	Is this step adding value, or is it waste?
Lean Six Sigma	Combines both perspectives