SDCA versus PDCA- when to use them.

I know many of us have been exposed to Plan-Do-Check-Action (PDCA), (note some earlier versions from Deming the PDSA (Plan- Do-Study-Act) cycle).  Both being a scientific, process oriented, approach to solving problems efficiently and effectively. 

Often times if we have a known standard in place and a measurable difference in the current state, I like to refer to that as a caused gap.   This means there are root cause(s) that need to be investigated and sought out at the gemba.  Basically a discrepancy in a process (doesn't have to be manufacturing).   Caused gaps use the PDCA process to get back to the original standard. 

Another usage of PDCA is for a created gap problem which is more strategic in nature.   A scenario could be I am meeting an expectation and looking or proposing or strategizing a new way or standard.  Raising the bar through continuous improvement bringing to life the visual staircase depicting kaizen. 

Here is a short video I did with The Lean Enterprise Institute using a visual to show caused versus created gaps:

During my tenure with problem solving I have come to the realization there are 3 commonalities when you get to the root cause analysis step.   Once confirming the true root cause based on facts you can categorize them into 3 bucket areas.  They will fall into either:

• Lack of a standard
• Not following a standard
• Wrong standard (not valid to the customer anymore)

So can you recognize the similarity?  - Standards!   I share with clients if all our A3's are telling us we needs standards I wonder how many A3's or problem solving events could be reduced if we just set standards to begin with.  Imagine that theory.  

One of my early lessons from my Japanese trainers was Standardize-Do-Check-Act - (SDCA).  This was a process we often used when we knew there wasn't a established standard and by potentially setting one that it "could" remedy the problem properly by following the process.  It's not as simplistic as it sounds and you have to gain some experience to determine when you use SDCA or PDCA.  Both processes can move the needle for your organization if the time is taken to practice.   

When using SDCA you start out with standardization first, putting what you know to be the best known standard in place that meets the internal and external customer needs.   Once you determine the correct standard you continue the process by putting it into place with the "Do" phase and "Checking" the effectiveness of your change based on the performance measures before you change and after.  Otherwise how are you going to know it was the right standard, so you must stay true to the process just as PDCA.   When you have determined it's meeting the expectation then the "Act" is to make it the new documented policy or procedure and share it with other affected areas.  This becomes the benchmark for improvement. 

As you develop your problem solving muscle you can begin to make the determination when its best to use PDCA or SDCA.   Either process must be followed thoroughly without taking the short cuts that are often driven by results of solving it quickly, instead the process of efficient and effective problem solving.  

Tracey Richardson - @thetoyotagal