Showing posts with label six sigma. Show all posts
Showing posts with label six sigma. Show all posts

Thursday, February 09, 2017

Should I be in the Check Phase of PDCA Daily?

Below is my response on closed forum about whether doing the "check" phase of PDCA daily was too often. I expanded on my comments there a bit in this post.

The check/study phase should be reviewing the results of the experiment done in the Do the experiment phase. "Checking" how things are going during the experiment makes sense but that isn't the check/study phase of PDSA .

For example, you don't want to pay no attention during the experiment and then look at the data and discover the data shows obvious signs the operational definitions were not clear, or the process is providing very bad results. So you need to have those doing the experiment paying attention daily.

Remember one key to using the PDSA cycle is to turn through the whole cycle quickly. Daily would be exceptionally quick. Moving through the whole cycle in 2-6 weeks is more normal. Organizations successful using PDSA will quickly turn the cycle 4+ times for a specific effort (often the 2nd, 3rd... times through are much faster than the first time through).

More on how to use the PDSA well:

Thursday, March 29, 2012

Examine the System, Don't Look to Blame a Person

Stress Solutions, Not Blame by Kevin Meyer
A couple years ago I told you how the organization had created a nonpunitive reporting system for air traffic controllers to report incidents. That led to a dramatic change, which might initially be seen as a scary negative but as most of us immediately realize is a huge positive:
New numbers released by the Federal Aviation Administration show reports of air-traffic errors have nearly doubled in three years. The number of reported incidents in 2007 was 1040, and that number rose to 1887 in 2010, an 81 percent increase. This cultural change in safety reporting has produced a wealth of information to help the FAA identify potential risks in the system and take swift action to address them.
The point of using in-process and process result measures on well functioning processes is often overlooked. You don't want to spend too many resources collecting data that has little value, but proper process measures are very useful and should be monitored. Also this helps when you decide to improve (or radically change something somewhat related) and can catch things (unintended consequences) very quickly. The point of understanding the data (in context) is critical. Brian Joiner did a very good job of emphasizing this idea I think. If you want to reduce complaints it is usually pretty easy to do so, by making it really hard to complain. When you really care about customer focus, understanding if complaints are up do to better processes to encourage complaints or because your service is lousy is critical. Related: Find the Root Cause Instead of the Person to Blame - Dr. Deming, 94% belongs to the system (responsibility of management) 6% special - European Blackout: Not Human Error (System Failures)

Friday, August 05, 2011

Experimenting to Discover

Causal Reasoning in Science: Don’t Dismiss Correlations (the broken link was removed)
Box, Hunter, and Hunter were/are theorists, in the sense that they don’t do experiments (or even collect data) themselves.
...
Science is about increasing certainty — about learning. You can learn from any observation, as distasteful as that may be to evidence snobs. By saying that experiments are “necessary” to find out something, Box et al. said the opposite of you can learn from any observation.
William Hunter was my father. He did many experiments. George Box did many experiments. You are entitled to your opinions obviously but the claim that they only dealt with other people's data is not accurate. It is true they were world renowned experts on experimenting and had many people consult them about their experiments, for help: designing them, analyzing them, what to do next, how to improve the process of experimentation in their organization, etc.. While it seems to be implied in the post that such consultation was a reason to distrust their thoughts on experimentation I hardly think that is a sensible conclusion to draw. Most of those they helped were running experiments in industry, to improve results (not to publish papers).

They were, and are, applied statisticians (and though I am obviously biased, I think many would agree, 2 of the most accomplished in that field in the 20th century). What experiments need to be done is critical for an applied statistician. What matters is making improvement in real world processes. If you don't run the right experiments, you won't learn things to help you improve.

They worked on the problem of where to focus, in order to learn, quite a bit. One significant part of there belief was to have those involved in the work do the thinking about what needed to be improved. This isn't tremendously radical today but in the past you had many people that thought "workers" should do what the college graduates in their office at headquarters tell them to do. Here is one of many such example, from Managing Our Way to Economic Success by William Hunter:

The key is that employees at all levels must have appropriate technical tools so that they can do the following things:

- recognize when a problem has arisen or an opportunity for improvement exists,
- collect relevant data,
- analyze the situation,
- determine whose responsibility it is to take further action,
- solve the problem or refer it to someone more appropriate...


I don't have the book in front of me, but doesn't it start with an example on learning where you can use inductive reasoning and from the facts that you see you can draw conclusions and construct a theory that fits the facts. If so, it seems to call into question the idea that they claimed "[the] opposite of you can learn from any observation." is not actually accurate. They understood you can use inductive reasoning to create theories. You then use experiments to test theories.

The books is called Statistics for Experimenters, right? Not statistics for drawing conclusions when not doing experiments. When you are experimenting you can test whether beliefs you have are accurate and you can learn about things you try. Smart people can make guesses what will happen and be right. I know the authors would believe those knowledgable about the system in question are well suited to determine what variables to test. It is that knowledge that will lead to experiments that are likely to be effective.

The authors of the book were trying to help those that often failed to learn as much from experiments as they could. Far too many people still don't use the most effective statistical tools when experimenting.

They emphasized, consistently, the need for those doing the work to involved in the experiments. The job of statisticians was to help in the cases where advanced statistical tools and knowledge would be useful. The reason for those who do the work (are familiar with the process) is because they have knowledge to bring to what should be tried in experiments.

When I read through The Scientific Context of Quality Improvement, 1987 by George Box and Soren Bisgaard it seems to me it discusses the types of issues you raise: how do we learn without experimenting? I am not sure if it is just me, or if it clearly addresses that issue. Here is another, Statistics as a Catalyst to Learning by Scientific Method by George E. P. Box. And another, Statistics for Discovery.

There are many other sources, I am sure. They understood the importance of learning as much as you could from available sources. They just also understood the importance of experiments and learning the most you could from experiments. And the book, Statistics for Experimenters, was focused on the most effective ways to improve using statistics to learn from experiments..

Here is what Box, said in his own words about the objective (and it isn't proving the hypothesis):

[too many people ]"can’t really get the fact that it’s not about proving a theorem, it’s about being curious about things. There aren’t enough people who will apply [DOE] as a way of finding things out"


Statistics for Experimenters: Design, Innovation, and Discovery shows that the goal of design of experiments is to learn and refine your experiment based on the knowledge you gain and experiment again. It is a process of discovery. That discovery is useful when it allows you to make improvement in real world outcomes. That is the objective.

Friday, December 31, 2010

Does a Good Lean System Need Six Sigma

With a good Lean system in place, do we still need Six Sigma? (the broken link was removed)

There is no Lean Team, but everyone in the organization thinks Lean. Employee satisfaction surveys show steady growth in satisfaction; profitability is increasing; cost are decreasing; less work pressure... The one problem still exist is ensuring JIT delivery from the suppliers network.

Can Six Sigma help the organization to accelerate or further improve this situation?


Good six sigma efforts (even 15 years ago) and lean share many of the same tools and principles that come from earlier TQM and such like efforts. There are some tools that are primarily associated with six sigma (like design of experiments). But those tools far precede "six sigma" even in their application in business. And those tools could certainly be useful in most lean organizations. There is no reason they couldn't just adopt those management tools.

Given that just in time was developed and made popular by Toyota and Deming long before the term six sigma was coined it certainly can be done expertly without six sigma tools. Six sigma tools can certainly help in my opinion, though.

I wouldn't weigh the benefit of any tools or methods or principles based on what category people places them in but instead I would build a management system based on the need of the organization. My preference is for Deming methods which form the foundation of lean and I also am a big fan of design of experiments (which most Deming and lean efforts do not use).

My father taught me design of experiments and Deming methods as a child and both have always made a great deal of sense to me. He wrote with George Box and Stu Hunter, what is seen by many as the premier design of experiments textbook, Statistics for Experimenters and he taught management improvement based on Deming's ideas, statistics, successful evidence based management principles... for decades.

These tools and methods all can be used together. A blog post of mine from 2005 on lean, six sigma, Deming, operational excellence and other management ideas.

Monday, August 09, 2010

Lean Six Sigma Health Care Sucess

Another Hospital CEO Talks Lean Culture

There’s a lot covered in the article – celebrating successes, communicating, and building on your successes. They also share a huge success in reducing waiting times for MRIs (from 25 to 28 days to just 3).


Great example. Senior leadership support and understanding is incredibly helpful. You can make progress without it. But eventually it becomes very difficult to work on the system without senior leadership support.

This example is also nice in showing that lean six sigma can work. So often organizations using the buzzwords don't have success. And it helps show different organizations can take different tactics. Many people don't like having a separate "improvement" office - as it can be seen to isolate it from everyday work. I think a separate, small, office, can help push improvement (especially in the first few years).

Related: lean manufacturing resources - blog posts on six sigma - resources for improvement health care management