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Today's Top 7 (or 8...) Quality Tools -

Traditionally, everyone in the process improvement world references the Seven Basic Quality Tools which were promoted by Dr. Kaoru Ishikawa back in the 1950s. Dr. Ishikawa was influenced by Dr. Deming, another quality great, and these are still a very good set of quality tools. But times have changed and the top quality tools should change with the times.

Among the dozens of tools out there (and there are over 100 Lean Six Sigma templates on our website alone) it can be overwhelming to decide which ones to use and when to use them.

Whether you’re working through a Green Belt Project or a conducting a simple Lean improvement effort, what are today’s Top Quality Tools? What is the simple, basic toolset that, used alone, could guide a person to successful process improvement? We’ll review the oldies and then share our current favorites:

The 7 Basic Quality Tools (of old):

  1. Cause & Effect Diagram: Structured brainstorming tool to get to root cause
  2. Check Sheet: The workhorse of data collection
  3. Control Chart: The best way to show process variation over time
  4. Histogram: A snapshot that shows the shape, center and spread of the data
  5. Pareto Chart: A visual ranking of most common problems
  6. Scatter Diagram: A visual display of cause & effect correlation
  7. Stratification: Ways to “slice” the data

Today’s Top 8 Quality Tools:

It’s been decades and due to inflation, we now have a “Top 8!” In order to reimagine the top tools, we have also reordered them to reflect when each might come into play. We’ve left the toolset intact with a few tweaks…

  1. A3 / Project Charter: A way to frame the issue or opportunity being addressed
  2. Process Map: A way to visually display the process, often the result of a Process Walk –  can be either a simple flow map or a Swimlane Map to identify who does what.
  3. Pareto Chart: A visual ranking of most common problems
  4. Histogram: A snapshot that shows the shape, center and spread of the data
  5. Cause & Effect Diagram: Also called a “Fishbone Diagram,” this is a structured brainstorming tool to get to root cause
  6. 5 Whys: A gift from Sakichi Toyoda, this is the essential partner of the Cause & Effect Diagram helping to dig past symptoms to root cause
  7. Value-Added Flow Analysis: A method of uncovering waste in the process
  8. Control Chart: The best way to show process variation over time

You could do a lot of good with just these 8 tools. What about you? What are your votes for top tools? In what order?

Tracy O'Rourke

Tracy is a Managing Partner & Executive Advisor at She is also a Lean Six Sigma Green Belt Instructor at UC San Diego and teaches in San Diego State University’s Lean Enterprise Program. For almost 20 years, she has helped leading organizations like Washington State, Charles Schwab and GE build problem-solving muscles.

Elisabeth Swan

Elisabeth is a Managing Partner & Executive Advisor at For over 25 years, she's helped leading organizations like Amazon, Charles Schwab and Starwood Hotels & Resorts build problem-solving muscles with Lean Six Sigma to achieve their goals.
  • Merlin

    excellent. We could also consider quality tools with an impact before the defect occurs (or just at the time) like Poka yoke and the great Jidoka, probably the best quality tool for me : analyse the defect is good, but analyse the defect when it occurs, where it occurs, with the people concerned by the defect is rather powerfull.

    • Tracy ORourke

      Excellent point Merlin. Thanks for sharing! It’s always nice to hear what tools people find the most powerful!

    • I’m with you on Poka Yoke Merlin – mistake-proofing is often so simple and has such an impact. And Jidoka goes way back to Sakichi Toyoda – that’s a great “old” quality tool from back when they made textiles instead of cars!

      • Merlin

        Thank you Elisabeth and Tracy. Concerning Jidoka, I meant the “modern” Jidoka, effectively inspired to Taiichi Ohno from the automatic loom of Sakichi Toyoda. Taiichi also called this application of Jidoka : “Autonomation with a human touch”.

        see a good insight :

        • You’re right Merlin – I should have given a nod to Taiichi Ohno, and thanks for the link. He did the job of updating it and tying it all into the TPS (here’s my take on Ohno:https: // – I actually wrote about Jidoka too:
          But I probably didn’t appreciate how some consider it the heart of the TPS – Always good to learn something new – thanks again!