Lean Manufacturing and Six Sigma Definitions

Glossary terms, history, people and definitions about Lean and Six Sigma


8D stands for the 8 disciplines of problem solving.

They represent 8 steps to take to solve difficult, recurring or critical problems (often customer failures or major cost drivers).

The structured approach provides transparency, drives a team approach, and increases the chance of solving the problem.

  • D1: Create a Team: Gather a cross-functional team of about 5 people with product/process knowledge, and have them gather information and data related to the problem or symptom
  • D2: Describe the Problem: Use the data and information to quantify and clarify the problem into a statement. Ask the 5W2H’s (who, what, where, when, why, how, and how many) for the problem.
  • D3: Develop Containment Plan: Define and implement interim containment actions to isolate the problem from any customer in the future.
  • D4: Determine and Verify Root Causes: Identify and verify all applicable causes and sources of variation that explain why the problem has occurred (special vs . common cause).
  • D5: Verify Permanent Solutions: Collect data to confirm that the possible solutions will actually resolve the problem. Perform on a small-scale or “pilot” project first.
  • D6: Define and Implement Corrective Actions: Discuss and review results, and develop plan to implement best solutions or countermeasure.
  • D7: Prevention: Modify the management systems, operation systems, procedures and practices to prevent recurrence of this and similar problems.
  • D8: Congratulate the team: Formally thank team members for their involvement. Use approaches that appeal to each individual member, as not everyone wants to be rewarded the same way.

Some versions of 8D include a D0, making it 9 steps (which creates a little confusion).

8D has become a standard methodology to improve processes, as it is much more prescriptive than A3 or PDCA.

The following improvement tools are often used within the 8D methodology:

  • Ishikawa diagrams (Cause and Effect diagrams, C&E diagrams or Fishbone diagrams)
  • Pareto charts or Pareto diagrams
  • 5 Why’s
  • 5W and 2H (Who, What, Where, When, Why, How, How often)
  • Statistical Process Control (SPC)
  • Scatter plots or scatter diagrams
  • Design of Experiments (DOE)
  • Check sheets
  • Histograms or Capability Analysis
  • Failure Modes and Effects Analysis (FMEA)
  • Flowcharts or Process Maps



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