One of the key things learnt from 6Sigma is the ability to accurately measure and analyze the information your organization collects. This can be as technical or as general as your organization needs, the key is to understand the level of specificity your organization needs and analyze from there. A Black belt will be able to give you in depth analysis, but a good one will give you exactly what your organization needs. We’ll start the discussion with Multi- Vari Analysis.
What is Multi-Vari Analysis?
Simply put this puts a face to the data. Once you have collected all of your information Multi-Vari studies take the data and illustrate the patterns of variation within the data. It helps you identify group or correlations between subgroups and over time. When you can identify the groups, you can make assumption or draw conclusions based on the data. For example if your data shows the your staff made more errors on product X you can draw the conclusion that your improvement efforts need to be focused on that particular product.
What is it used to assess?
Multi-Vari studies are useful in many ways but the most standard uses are
- to illustrate data in graphics.
- to show how work is influence by defined variables.
- to show the impact of specific material, departments or methods.
- the effects of external factors such as noise, delivery delays etc.
When you need to show stakeholders, influencers or project staff what you have found multi- vari studies are a great way to produce a visual. Since most people learn by doing, a visual representation allows them to see what they have done and to show leadership the gains or losses accordingly.
We’ve spent a fair amount of time learning the ins and outs of MSA’s, so this week I want to focus on process capability and how to understand the information you receive.
What is Process Capability?
In a nutshell Process Capability is:
• What it takes for your process to meet your customers’ needs right out of the gate with no modifications. This means for lack of a better term, inherent perfection.
• The information that can be provided on centering, variation and inappropriate measurement limits.
• The baseline metric for improvement
When determining your process capability there are three types of capabilities that we analyze:
• Continuous Capability- If you process is capable and in control, ideally you should get your desired outcome. This analysis measures the life cycle of your process telling you if the process has continued to be capable and in control.
• Concept of Stability-The idea of stability is the ability to answer the question ‘will my process produce the same result at this step every time it is used?’ To be technical, stability measures the ability of your process to meet its requirements at a regular and specific interval.
• Attribute Capability-This analysis makes assumptions about your data and is always long term data.
This week we’ve just scratched the surface on Process Capability. Next week, we’ll start digging a little deeper and show some illustrations of what it looks like.
As we go over Six Sigma statistics, we have to talk about normal distribution. Before we get to that though we have to talk about why distribution is important to the way you interpret your data. In interpreting your data there is something you should know before you tackle how the information observed, confidence intervals. Confidence intervals is more complicated than this blog, but basically what you need to know is the greater the confidence level the less likely the variation is to occur and the more you can guarantee the accuracy of data analysis. In confidence levels there are 3 common ones that we use in data analysis, 99%, 95% and 90%. The standard of measurement is 95%, the higher the better but as a baseline 95% is a solid analytic benchmark.
Okay so back to normal distribution. Here’s what you need to know.
What is it?
You find normal distribution when you take all of your data and create a visual representation of the information. You will illustrate when recurring variations show up in your process. It is actually more helpful when you have a distribution that isn’t normal because then you can say ‘Aha it was the 3 hour traffic jam that affected the process’. When you hear people talk about the curve, this is what they are referring to.
When do you use it?
This is a tool that is best when used as a continuous probability model with measurements that you don’t have to create. Think about the weight of a cargo shipment or the number of a specific product you receive.
Raw scores and Z scores
Each normal distribution will have a raw score which is made up of two parameters: the mean and the standard deviation. The Z score measures how far you varied from a particular point on your data line. In real terms it means, if you want to see how many errors occurred on the 5th then standard deviation shows you that.
Why is it important?
The area under the curve shows the proportion of the curve and which tells you how important this data is to your business. Is the curve is small then you now that the distribution occurs within a relatively small set of circumstances which is easier to control within process. A wider distribution shows you that your process can be interrupted by a variety of factors and may need you to keep a close eye on it.
This week we will continue our discussion on process mapping, I promise it will not go on forever, but it does have a lot of intricacies. Many people think that process mapping is just putting some shapes on a diagram, but it means much more than that. There are 3 levels of process mapping that are commonly accepted among the 6Sigma crowd.
Level 1 –The Macro Process Map
This is typically how management views the processes of the organization; it’s a big picture, future strategy kind of view. It also creates the ability for management to see how to position the organization or resources in a way that complements the product/service being created. This is a high-level map which generally includes:
- Activities that relate to one major process step
- How the process fits into the big picture
- Little specific detail
- Visualizes only major process steps
- Can be used with only a general understanding of the purpose of the process and its steps.
Level 2-Process Map
This is the worker bee process map, where the people who have specific knowledge of the process come in. This is the map that is used to identify all the major steps a worker takes to complete a process. Within Level 2, there are 4 types of process maps:
- Linear Flow- A straight line from beginning to end.
- Swim Lane-shows you who is responsible for what task.
- SIPOC-a little more complicated. It takes five areas: your suppliers, your inputs, your process, your outputs and your customers.
- Value Stream-a specific map that helps to visualize and understand the metrics for the performance of major steps.
Level 3-Process Flow Diagram
Level 3 is not a must because this is a micro process map. It is where you zero in on a specific area and focus on the steps in the process that are causing whatever challenge you are having. When beginning this level you need to ask the following questions:
- Which steps contributed to the problem?
- Where would the problem most likely have occurred?
- Are there elements to the product/service that lend itself to the problem?
These questions help you find the focus that you decided in your problem statement. For this to work you will have to break each step in the process down, most easily using SIPOC. Remember a Level 3 map should include:
- All process flows
- Any set points
- Any standard or automated procedures
- Inputs and outputs (specify if the are controllable or non-controllable)
- Defects per unit
- Yield and rolled throughput yield
- Value and non value added activities
It’s a lot of information, but mapping a process is a fundamental step in your improvement project. It is absolutely critical that you get it right. For more help or more information, give us a call and we will be happy to get you started.
In any lean project there are a ton of buzzwords, but the one thing that is a universal truth in all lean initiative is that for any tool used to be successful it must be understood. In today’s blog we are going to talk about a Gemba walk and why it works.
What is it?
A Gemba walk is literally seeing where the work happens and the value of work. The reason for the walk can be varied but its importance is to illustrate the process to the people who will be responsible for improving it. I like Gemba because it takes 6Sigma out of theory and metrics and illustrates it in a tangible way that makes sense to the people using it.
What do I do?
This is by no means a comprehensive checklist, but it is a place to start when you are planning your Gemba walk. I provided a simple but comprehensive checklist to create your Gemba walk below.
- Identify the processes (internal/external) that the customer pays for and has an expected output.
- Identify who understands the process- What you are looking for here is not the person/division/team responsible for the process, but the person who designed the process and understands why it operates the way it does. This person should understand the performance gap analysis and have a plan to correct the gap (or at least the beginning of an idea).This step is hard for a lot of people because the knowledge master generally isn’t the person with the official responsibility, but it is critical that you get this step right.
- Focus on the steps of the process that add value, show standardization or show how the work is distributed.
- Know the expected outputs-Are they gaps? Are you asking why? Are you assigning blame? (If are, you shouldn’t be.)
- Identify the areas of the process that are going well, what is making that success happen?
- Now that you know what is working and what is not, create your checklist based on this information.
- Remember to steer clear of the 3M’s and educated your process leaders on them. Muda-Waste, Mura-process variation not caused by the customer, and Muri-overburden on facility, people and equipment caused by Mura and Muda.
This is pretty comprehensive checklist, but as with all my posts this is just to introduce you to the Gemba Walk tool. Consulting with your belt will give you the most useful questions and sources of information in your walk. Done correctly a Gemba walk jumpstart rapid improvement events, done incorrectly they can derail an entire initiative. What will you value today?