Lean Six Sigma Yellow Belt
After completing this course, you will be able to:
- Understand the key principles of Lean Six Sigma
- Identify improvement opportunities in your organization (projects)
- Understand and use the Define, Measure, Analyze, Improve, Control (DMAIC) model and key activities
- Use the basic tools and techniques
- Understand the role of Yellow Belts in Lean Six Sigma projects
- Run small improvements in their day-to-day work processes
The modules covered in this learning:
- Lean Six Sigma Overview
- Define Phase
- Measure Phase
- Analyze Phase
- Improve Phase
- Control Phase
The recommended study time for this course is approximately 5 hours.
Please note: this content was produced in the UK and may include the use of British English.
Key exam information
There is no exam at the end of the LSSYB. A Yellow Belt certificate is issued upon completion of the training.
Welcome. This is part two of the analyze phase. In this phase, we will look at the five whys and the cause and effect diagram. The next tool that's often used in process improvement is known as the five whys. It's a very simple concept. A problem or an issue arises and you keep asking why until you get down to the root cause. In fact, there is no magic number five. It was just felt at the time when the idea was considered that by the time you've asked why five times, that should be more than enough to get the root cause.
However, to avoid this number five, some people call this repeated whys. You might get to the root cause in three, you might get to it in six. The number is not important. It's the concept of constantly asking why to get down to the root cause. The five whys is often used with another technique called the cause and effect diagram, which we will see later.
So how does the five whys work? In this simple example, we will consider the situation where my laptop will not start. I ask why, and discover that there's no power. Why is there no power? My battery's flat. Recharge the battery and my laptop will start. So the battery being flat is the direct cause of my laptop not starting. If that is all we do, then we can expect in the future, for the battery to go flat again because we haven't understood why it went flat in the first place. So I would always recommend to keep going beyond the direct cause, to the root cause of that direct cause.
So let's do that here. My battery's flat, why? I'm unable to recharge. Why am I unable to recharge? I've no power lead. So clearly here, if we get a power lead and use it to recharge, we will not have a laptop that will not start because of the flat battery. However, when you use the five whys, you do need to apply some common sense as to where to stop as you can keep going. However, if you go too far, you will discover that the results become nonsense. But let's try that here. I've no power lead, why have I no power lead? I've lost it. Why have I lost it? I'm careless, why am I careless? Personally I blame my parents. So the reason my laptop won't start is because of my parents which is not gonna help one bit in trying to improve this process. And so when using the five whys, do apply some common sense.
Now, in this example, you will see that the answers to the five whys are put in a series of stairs. This gives the idea of flow. We come down the stairs asking, why? We go up the stairs asking, what is the effect? By doing this we can check the logic of what we've done. We can also extend the top of the symptoms. In this case, my laptop won't start, I can ask what is the effect? And maybe, that is I can't access my emails. So the real issue here is, I need access to my emails. Knowing that, we can ask, is there a short-term way of accessing emails while we get the laptop fixed? So, using the five whys helps you gain a better understanding of the situation and the root cause.
In process improvement, the five whys is used a lot. It may not be drawn but very often people will keep asking why to try and understand what's going on. So someone might come and say, oh this has just happened. You ask, well why did that happen? Oh because of this and this. Well why did they happen? Because of this. And so it does become part of the natural way of investigating what's going on.
Another technique, which is often associated with the five whys, is a cause and effect diagram. The cause and effect diagram was developed by a Japanese engineer called Ishikawa. However, because of its structure, which you will see soon, most people call it a Fishbone. In the head of the fish, you put the effect or the problem. Then off the bones, you put some meaningful headings that will help you understand what are the potential causes of the effect or the problem. Some of the most useful headings are materials, equipment, people, environment, methods, measurement. In non-manufacturing, sometimes people like using people, place, policies, procedures.
The headings themselves are there to help the group brainstorm ideas of what the potential cause is of the effector. So in the head, we write the effect. So we may put, why are people late for meetings? So the first part would be, let's look at people. So what is it about people that make them late for meetings? And we might put things like, poor timing keeping, no interest in the meeting and continue until we've exhausted that. Then, we might consider what is it about the environment that means they're late for meetings? And answers might be, they have to travel, there's lots of congestion at the lifts. You would continue using each heading until you have exhausted all the potential solutions to the effect.
Once the brainstorming has been completed, we lose the headings as we're only interested in the potential causes. The Fishbone is one of the seven quality tools that was introduced into process improvement by Ishikawa himself. However, of the seven quality tools, the Fishbone is different in that it is the only one that is based on opinions and not facts. And so, once you've collected all the potential causes, I would always advise that you go back to the process and try and collect data to identify which of those potential causes are really creating the effect or the problem.
Collecting this sort of data, you would then probably display it in a Pareto chart. And as said before, work on the largest bar to try and understand the root cause and what can be done to stop that occurring. Here is an example from a collections department of a financial services. In this case, the team were looking at why they were not meeting their recovery income targets. They have some very interesting headings: performance incentives, management information, debt management, capacity planning. Under each of these, they've brainstormed some potential causes. However, these are only potential causes and they need to collect some facts as to which one of those potential causes are causing them not to meet their targets.
This is the end of part two of the analyze phase. In part three, we'll be showing you how to analyze the process.