Six Sigma: PDCA on Steroids?

Whenever I attend a Six Sigma symposium or healthcare conference, the same question comes up: “What’s the difference between Six Sigma and what we’re already doing?” Of course my response is, “Tell me more about what you’re doing so I can better answer that question.” After fielding this question for over a year, I’ve come to several conclusions:

  • There is a certain level of variability in the way healthcare systems attack internal quality or process improvement issues.
  • Depending on the particular methodology a hospital is using, the differences can be anywhere from glaringly obvious to fairly difficult to ascertain.
  • There are a few extremely critical areas within the Six Sigma methodology that set it apart from other processes.

The following is offered as a brief comparison between the Six Sigma DMAIC process and FOCUS-PDCA. The DMAIC process includes phases for Define, Measure, Analyze, Improve and Control. FOCUS-PDCA is an extension of the plan-do-check-act (PDCA) cycle, sometimes called the Deming or Shewhart cycle, and is considered the most in-depth of the PDCA or PDSA methodologies. FOCUS is an acronym representing the five phases of the process known as Find, Organize, Clarify, Uncover, and Start. As with other quality initiatives such as TQM or CQI, there are some similarities with Six Sigma, however there are also significant contrasts and gaps that should be examined.

Find a process to improve
  • Define the problem
This is the equivalent of Step A in the GE Six Sigma process.The difference is that Six Sigma provides templates, tools and roadmaps with deliverables for each step that are completed before moving forward.
Organize to improve the process
  • Identify/develop a team that knows the process
This is the equivalent of Step B in the GE Six Sigma process.Again more templates and tools are used on the Six Sigma side. In some companies, change acceleration tools are also used to address the acceptance side of improvement initiatives.
Clarify current knowledge of the process and collect information
  • Identify current process
In Six Sigma, this would be Step C “process map” and Step 4 “how good is the current process”.Focus PDCA is missing steps 1, 2, & 3

Step 1: CTQ Characteristics

“What do I want to improve”

Step 2: Define Performance Standards

“What’s the best way to measure”

Step 3: Validate Measurement System or GRR

“Can I trust the output data

Understand the source of process and collect variations
  • Identify root cause of the problem
  • Address system issues staffing equipment, supplies, etc.)
This would be 1/2 of Step 7 if your problem was around critical elements, “What’s at the root of the problem”.FOCUS PDCA is missing steps 5, 6 & 7 (for operating parameters or OP only)

Step 5: Define Performance Objective

“How good do I need to be?”

Step 6: Identify Variation Sources

“What factors make a difference”

Step 7: OP problems

“can I turn the problem on & off”

Select the process improvement
  • Generate solutions
  • Make appropriate recommendations


  • State what change is expected
  • Select the solution
  • Identify who is responsible for the action plan
  • Identify staff members assigned to carry out portions of the plan
  • Identify the required action (education, focused, supervision)
  • Identify who is responsible for education supervision
  • Recommend system changes
  • Identify/select/develop tool for monitoring the expected change


  • Implement plan
  • State target completion date


  • Identify desired compliance goal
  • Identify monitoring dates
  • Monitor the effect of the change
  • Identify staff members responsible for monitoring and data managers
  • Analyze data and determine % compliance met
  • Determine if the plan was a success
  • Identify people/system issues that impacted the success of plan
This is the second part of Step 7: Once you’ve identified root causes you develop solutions.This would be 1/2 of Step 7 if your problem was around critical elements, “What’s at the root of the problem”.

FOCUS PDCA is missing steps 8-12:

Step 8: Discover variable relationships

“How can I predict the output”

Step 9: Establish OP tolerances on X’s

“How tight does the control have to be ”

Step 10: Validate X Measurement System

“Can I trust the in-process data”

Step 11: Determine Process Capability

“Have I reached my goal”

Step 12: Implement Process Control

“How can I sustain the improvement”

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From my perspective, whether Six Sigma Steps are included or omitted the significant difference between Six Sigma and FOCUS-PDCA is that in FOCUS, there is no roadmap. In addition, there are very few tools and templates to help navigate through the methodology to ensure successful identification of problems and appropriate resolutions. If you are successful, the success could be just as easily attributed to your expertise or knowledge of the area, versus the methodology you used. With Six Sigma, a person knowing little to nothing about an area can still come to the same conclusions in the same amount of time, if not quicker. Furthermore, a novice using the Six Sigma methodology will be able to convey how confident they are in their analysis and subsequent recommendation using statistics instead of intuition.

Finally, the people side of any process improvement requires as much work as the technical side, and sometimes more. This is not addressed anywhere within the FOCUS-PDCA cycle. Built into the Six Sigma methodology is an arsenal of over 30 tools, some mandatory and others optional, to ensure that the impacted business area agrees on the recommended solutions. These tools also help address issues related to the systems and structures after the project is complete, ensuring sustainability.

There are opportunities to integrate the Six Sigma methodology where businesses have already adopted FOCUS-PDCA. Such integration would offer a robust process improvement methodology without reinventing the wheel. The modifications would focus on gaining acceptance from the key stakeholders, everyone from front line technicians to clinicians, management and board members. It would also require putting control mechanisms and systems and structures in place to ensure that successful project improvement outcomes are sustained over time.

Comments 5

  1. Jacques Pineault

    If you read Jeffrey Liker’s books on “The Toyota Way”, you will find out that DMAIC is far from being PDCA on steroids. Actually they are not the same at all. Jeffrey is most likely the biggest authority in the Toyota Production System, outside of Toyota obviously, as he has spent 30 years and more at studying that system.

    In the book “The Toyota Way to Continuous Improvement, Jeffrey make the comparison between PDCA and DMAIC.

    DMAIC (Western PDCA) Toyota’s PDCA
    Purpose Predict and control process Learn by trying
    Goal Solve problem Improve process and develop people
    Assumption World is predictable, like a machine World is dynamic and uncertain,like a living organism
    Planning Process: Statistical tools Deep understanding and build consensus
    Analyst Expert with group input Work group with expert support
    Do Implement solutions Try countermeasures
    Check Confirm hypothesis Find further opportunities for improvement
    Adjust Process Standardize proven process Standardize what works, share learning, identify . and replicate best practices further problems for PDCA

    So, Ruth, when you write”With Six Sigma, a person knowing little to nothing about an area can still come to the same conclusions in the same amount of time, if not quicker.”, well, that way is not working because it’s not providing lasting results. You can never put somebody with tools (statistical tools only and no deep understanding) to replace somebody who knows the art of doing something ( a deep understanding of the situation).

    To be successful, Six Sigma people and Lean Six Sigma people must work in teams with the people who know the art. Otherwise, you end up with the very high failure rate (above 70%) of improvement initiatives that are not done with the lasting support and the continuity required.

  2. Jacques Pineault

    (Sorry. I had to redo the table to keep the format)
    ………………………..DMAIC (Western PDCA)………………..Toyota’s PDCA
    Purpose……………..Predict and control process…………….Learn by trying
    Goal………………….Solve problem………………………………Improve process and develop people
    Assumption………..World is predictable, like a machine…..World is dynamic and uncertain,like a living organism
    Planning Process…Statistical tools…………………………….Deep understanding and build consensus
    Analyst………………Expert with group input…………………..Work group with expert support
    Do…………………….Implement solutions………………………Try countermeasures
    Check………………..Confirm hypothesis……………………….Find further opportunities for improvement
    Adjust Process…….Standardize proven process…………….Standardize what works, share learning, identify ………………………..and replicate best practices…………….further problems for PDCA

  3. Jim M

    I have black belt and find it easier to train others using FOCUS PDSA

    If I do a project, I can use DMAIC no problem, but not everyone has full time job of process improvement

  4. charles

    Nice comparison. From a service perspective my experience is that service organisations are more predisposed to the Focus PDCA approach as the 15 step process is overblown and time consuming for most service processes relative to the benefits of using the various statistical tools eg validate measurement system. Furthermore most managers have little understanding of these tools and perceive such tools as self indulgent and time-wasting

    By the way, you left the ‘A’ = Act/Adjust, off the PDCA table

  5. Nick Vaccarino

    I thought the article was very good having utilized both practices over the years it is almost a coin toss as to which is better. Ultimately which ever process you follow your organization is improving hopefully on a long term basis,

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