Every organization has problems that get “solved” over and over again, only to reappear. Teams work hard for months, generating solutions that people just know will work… but don’t. This is another type of failure that Lean Six Sigma can’t afford. That’s why it uses a modern problem-solving method designed to avoid such problems. The model is called DMAIC (pronounced duh- MAY-ick), which stands for Define-Measure-Analyze-Improve- Control.
DMAIC has proven itself to be one of the most effective problem-solving methods ever used because it forces teams to use data to…
If you go through Lean Six Sigma training, you’ll learn a lot about DMAIC and its data-based methods that are called “problem-solving tools.” In this chapter of the book, we just want to introduce you to the logic of DMAIC and spotlight a few tools it uses to prevent the kinds of problems many teams used to run into. The next chapter will describe case studies where DMAIC was used to solve real problems.
Before we get into the DMAIC process itself, you should be aware of what happens before a team gets started. Your management team will likely go through a project selection process to identify the projects they want to launch. The Champion (the corporate-level executive leading the Lean Six Sigma effort) will help your supervisor or manager draft a project charter to document what they want the team to accomplish. The charter is usually short—just a 1- to 2-page form. Some companies find it helpful to use a form similar to that shown in Figure 8.1.
Figure 8.1: Sample Project Charter
What’s important to know is that the charter you’ll be handed if you serve on a team is just a draft. Your team will be expected to fine-tune it once you begin studying the problem in detail. In some cases, you may discover information that will make management re-think the decision to work on the project in the first place. Or the problem may be much bigger than they thought, and there’s no way the team can tackle it. (So the team will have to work with management to agree on what some reasonable goals are.)
Teams should refer back to their charters throughout their projects. For one thing, this helps remind them about what they are supposed to do. It also gives them a chance to update the charter as they learn more information about the problem and its likely solutions.
The Define-Measure-Analyze-Improve-Control (DMAIC) process is usually described as a “structured, data-based problem-solving process.” That means:
The purpose of this first stage of the DMAIC process is for a team and its sponsors to agree on what the project is. The kinds of things you’ll do include…
Why should you do these things? They help you…
A core principle of Lean Six Sigma is that defects can relate to anything that makes a customer unhappy—long lead time, variation in lead time, poor quality, or high cost, for instance. To address any of these problems, the first step is to take a process view of how your company goes about satisfying a particular customer requirement. The tool for creating a high-level map of the process is called SIPOC, which stands for:
Suppliers: the individuals or groups who provide whatever is worked on in the process (information, forms, material)
Input: the information or material provided
Process: the steps used to do the work
Output: the product, service, or information being sent to the customer
Customers: the next step in the process, or the final (external) customers
An example of a SIPOC diagram is shown in Figure 8.2. A project team in a company that leased equipment was asked to reduce the number of errors in orders and corresponding invoices. As a first step, they created the SIPOC diagram to identify the basic elements of the process they were supposed to study.
Figure 8.2: SIPOC process diagram
SIPOC diagrams present a very simple view of a process, and are very useful for visually representing the basic elements of a process under study. But they don’t really help a team under- stand what needs to be changed in a process. For that, you need more detailed process maps (also called “flowcharts”).
One type of process map used frequently in Lean Six Sigma projects is called a value stream map. These maps not only show the process flow, but also display actual process data. (See example in Figure 8.3, top of next page). Because they include data, value stream maps can help teams pick out specific points in the process that have problems such as long wait times or lots of errors.
Figure 8.3: Value Stream Map
Measure is the heart of what makes Lean Six Sigma work when other approaches haven’t. If you don’t gather data, you’ll likely end up with a lot of quick-hit projects with short-lived or disappointing results. Combining data with knowledge and experience is what separates true improvement from just tinkering with a process. In Measure you will…
Actions like these are necessary so you can…
We’ve already talked about the need to document or “map” a process. But before you even get to that point, what you need to do is simply go out and watch what’s going on. In the famous words of Yogi Berra, “You can observe a lot just by watching.” There simply is no substitute for impartial observation as a way to confirm what really happens in a process and identify waste and inefficiencies that are built into how work is currently done.
A Time Value Map looks at how time is spent in a process. The chart consists of a timeline with bars broken out to highlight work that adds value in your customers’ eyes and work that doesn’t. One example is shown in the Figure 8.4 on the next page.
Figure 8.4: Time Value Map
One of the reasons why many improvement efforts have failed in the past is that people make general changes targeted at general problems. What’s different in DMAIC is that you use data to pinpoint a specific cause of the problem. Then you develop solutions for that specific cause.
One of the most common tools used to help focus a team’s efforts is a type of bar chart called a Pareto chart (pronounced “puh-RAY-toe”—it’s named after an Italian economist). In a Pareto chart, each bar represents a different element of a problem. The height of the bar shows how much of the problem is due to that cause, and the bars are arranged in descending order (as shown in Figure 8.5, previous page). Almost always, the first few bars will be tall, and the rest will be much shorter. That means you can solve most of the problem if you take care of the issues represented by the tall bars—that is, focus your efforts on the few biggest causes.
Figure 8.5: Pareto Chart
A time series plot is a chart where data points are plotted in sequence along a timeline (see Figure 8.6). Time plots are an important DMAIC tool for several reasons:
Figure 8.6: Time Series Plot
The challenges of data collection
If you’ve ever tried to gather data, you’ve probably encountered one or more of the following roadblocks:
If any of these conditions hold true for your team, expect to spend a lot of time deciding what data to collect and finding a way to collect it.
The purpose of the Analyze phase is to make sense of all the information and data collected in Measure, and to use that data to confirm the source of delays, waste, and poor quality. A challenge that all teams face in Analyze is sticking to the data, and not just using their own experience and opinions to reach conclusions about the root causes of problems. The things you’ll do include…
These actions will allow you to…
A cause-and-effect diagram is a “thinking” tool that helps a team organize the ideas they have about potential causes of a problem. Organizing ideas this way serves two purposes:
A cause-and-effect diagram is sometimes called a fishbone because it resembles the skeleton of a fish. As you can see in the example on the next page (Figure 8.7), the team’s problem statement is named in the “head” of the fish, with potential causes arranged in sets of “bones” linked to the head. The smallest bones are the most specific types of causes that contribute to the next larger level of bone, and so on.
Figure 8.7: Example cause-and-effect diagram
Cause-and-effect diagrams do not tell you which of the potential causes is the culprit. They are just a good way for the team to document which theories it has considered, which have been targeted for further investigation, and, ultimately, which have been verified.
The scatter plot is a simple tool that can help determine if a relationship exists between two measures or indicators. The example shown in Figure 8.8 (top of next page) was created to explore whether broker experience affected how long it took to complete client calls. The downward slope of the line shows that more- experienced brokers are able to complete calls more quickly.
Figure 8.8: Scatter Plot
If customer satisfaction was high with the shorter calls, the team would then have to see what the experienced brokers knew that let them get done faster, and transfer that knowledge to less-experienced brokers.
Scatter plots provide a powerful visual image of how potential process factors are (or are not) related to a key outcome. Often, the visual impression is enough to confirm (or rule out) a specific course of action. If necessary, more advanced statistical tools can be used to quantify the degree of relationship between the two factors.
The sole purpose of Improve is to make changes in a process that will eliminate the defects, waste, costs, etc., that are linked to the customer need identified in the Define stage. The links in the last sentence are critical. The team must make sure that the causes they’re looking at in Improve affect the problem or need defined in its charter. The changes they make must affect the causes they confirmed in Analyze. The things you’ll do include…
What does this get you? It will help your team…
There comes a time in every project where the team has developed a number of alternative solutions they think could improve the problem. There are several ways that they can compare those alternatives. One of the simplest to construct is the PICK chart (Figure 8.9, top of next page). On this type of chart, your team just needs to identify how much effort it will take to implement your solution ideas, and what kind of payoff you expect. Performing this analysis helps you decide which ideas you should implement for sure, which may need more work, and which ones you should just abandon.
Figure 8.9: PICK Chart
A manager who wants to prepare a monthly report starts gathering together the information he needs. He realizes that this month’s sales figures aren’t broken out by region, so he calls over to accounting and tells them to email the regional split as quickly as they can. He also discovers that he has updates on only three of the four Lean Six Sigma projects in his unit. So he spends about 20 minutes tracking down a Black Belt and getting a verbal update on the fourth project. Then all he has to do is get the month’s wages/benefits figures from HR, and he’s ready to work on the report.
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Dave, one of the more experienced technicians in IT knows more about PCs than nearly anyone else in the company. Trouble is, the graphic design group is on Macintoshes. So even though Dave spends 95% or more of his time supporting the PC users, he still has to answer a handful of calls each month from the Mac users. He describes the experience as having to “reconfigure” his brain so he can switch from thinking in Microsoft Windows to thinking in Apple’s OS X.
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The people who work on the old machinery down in the steel plant dread the days when they have to process a number of different grades of steel. Changing steel grade means adjusting the machines. Minimally, they lose about a half hour each time they have a changeover. And that’s if everything goes right, which it doesn’t always. That’s why most of the time they produce a lot of one grade of steel at a time, even if no customers need it.
Odds are that at least one of these examples reflects what happens in your job—needing to track down information to finish a task, switching from one set of tasks to another, doing work in large “batches” because it seems easier, having some element of your job that you only rarely perform. Can you tell what they all have in common?
The answer is that all of these processes have problems that divert people away from their “value-add” work. If they could have the information at their fingertips, if it was easier to switch from one computer system or grade of steel to another, these people could get a lot more work done. Problems like these slow down a process.
In Lean terminology, the situations described above are all considered setup problems that delay or interrupt people as they try to complete the “value-add work.” The Lean tool for attacking setup time is the Four-Step Rapid Setup method. The actual procedures are too detailed to go into in this book. Very briefly, the four steps cover techniques like doing prep work in parallel with value-add work, eliminating the need for set up work, and so on. In short, the principle of this method is to eliminate anything that interrupts or hinders productivity.
Here’s an example from a service situation (the principles hold true for manufacturing as well). The buyers in one division of Lockheed Martin had to purchase parts for 14 different business units—each of which had its own computer system. To process the purchase orders, a buyer would log onto one unit’s system, work through all of its purchase requests, log off that system and onto another unit’s system, and so on. Switching from one system to another could take the buyers as much as 20 minutes at a time—which is why they would do all the orders from one unit before going on to the next.
Because of the large number of purchase requests, it could take a buyer a full day to complete the orders for one unit. With 14 units, that meant each unit’s orders would be handled only once every three weeks! Is it any wonder that the units complained about how long it took them to receive the materials they wanted?
The Four Step Rapid Setup method challenges people to think about work like “switching computer systems” in new ways. Can it be eliminated? If not, what can be done to make it simpler and shorter?
In this case, the answer was that yes, it could be eliminated. The team worked with the technology department to develop a system where all the orders from all the sites were automatically downloaded into a central database every day. So the buyers just had to log into one database to see all the orders from all the units. They could also tell which requests were high priority and process those first.
Most likely you won’t have heard of the Four Step Rapid Setup method before. So why did we take so much time talking about it? For two reasons: At a general level, we wanted to show that the Lean Six Sigma toolkit includes tools that help you develop solutions as well as tools for gathering and understanding data. More specifically, the Four Step method is often THE critical tool for accelerating process speed. In the Lockheed Martin example discussed above, for example, the average time it took for buyers to enter orders went from 14 or more days on average to 1 or 2 days.
The purpose of Control is to make sure that any gains your team makes will last. That means creating procedures and work aids that will help people do their jobs differently from now on. The team must transfer what they learned to the process owner and ensure that everyone working on the process is trained in using the new, documented procedures. In Control you will…
The actions will help you…
Probably the most common tool in Control is a control chart, which you can think of as a super-charged time series plot. Like a time plot, the data points are plotted in time order. But control charts have additional lines on them (control limits) that are used for interpreting patterns in the data. (See example in Figure 8.10.) Basically, if any points go outside the control limits, that’s a signal of unusual variation. Someone should investigate what’s going on in the process right away. (In addition, specific patterns of points within the limits are also used as signals.)
Figure 8.10: Control Chart
Control charts look complicated, but they are fairly easy to construct based on some simple mathematical formulas. Team members will often get help from a Black Belt and/or statistical software for constructing these charts.
It takes discipline to find real solutions to problems. The DMAIC framework provides that discipline and structure to teams. It can sometimes seem tedious to work through all the steps of Measure and Analyze—gathering data, learning lessons, realizing you have to gather even more data. Perhaps the biggest challenge you’ll face is the temptation to skip all the messy stuff in the middle and go right from defining the problem to implementing solutions.
If you work on a DMAIC project, we promise that you’ll have periods where you think it isn’t worth it. When that happens, keep in mind that DMAIC wasn’t developed by people who had nothing better to do with their time. It’s the result of years of experience from people who’ve learned the hard way what it takes to make improvements that last.
Foundations of Lean Six Sigma
Implementing Lean Six Sigma