between Lean and Six Sigma – your organisation needs both. Many people think of Lean as focusing on improving the efficiency of processes, and Six Sigma as concentrating on their effectiveness. The reality is that both approaches tackle efficiency and effectiveness.
Chapter 2
Understanding the Principles of Lean Six Sigma
In This Chapter
▶ Merging Lean and Six Sigma to make Lean Six Sigma
▶ Undertaking DMAIC to make things better
▶ Reviewing what you do in order to do it better
In this chapter we look at the synergy produced by combining the approaches of Lean and Six Sigma to form Lean Six Sigma. The merged approach provides a comprehensive set of principles, and supporting tools and techniques, to enable genuine improvements in both efficiency and effectiveness for organisations.
Considering the Key Principles of Lean Six Sigma
Lean Six Sigma takes the features of Lean and of Six Sigma and integrates them to form a magnificent seven set of principles. The principles of each approach aren’t dissimilar (check out Chapter 1 to read more about the individual components), and the merged set produces no surprises. The seven principles of Lean Six Sigma are:
✔ Focus on the customer. The customer’s CTQs describe elements of your service or offering they consider Critical To Quality (see Chapter 1 for more on these). Written in a way that ensures they’re measurable, the CTQs provide the basis for determining the process measures you need to help you understand how well you perform against these critical requirements. Focusing on the customer and the concept of value-add is important because typically only 10–15 per cent of process steps add value and often represent only 1 per cent of the total process time. These figures may be surprising, but they should grab your attention and help you realise the potential waste that’s happening in your own organisation. As you improve your performance in meeting the CTQs, you’re also likely to win and retain further business and increase your market share. The concept of value-added process steps is covered in Chapter 9, and Chapters 3 to 5 consider the customer in more detail.
✔ Identify and understand how the work gets done. The value stream describes all of the steps in your process – for example, from a customer order to the issue of a product or the delivery of a service, through to payment. By drawing a map of the value stream, you can highlight the non-value-added steps and areas of waste and ensure the process focuses on meeting the CTQs and adding value. To undertake this process properly, you must ‘go to the Gemba’. The Japanese word Gemba means the place where the work gets done – where the action is – which is where management begins. Process stapling (which we introduce in Chapter 5) involves you spending time in the workplace to see how the work really gets done, not how you think it gets done or how you’d like it to be done. You see the real process being carried out and collect data on what’s happening. Process stapling helps you analyse the problems that you want to tackle and determine a more effective solution for your day-to-day activities.
✔ Manage, improve and smooth the process flow. This concept provides an example of different thinking. If possible, use single piece flow, moving away from batches, or at least reducing batch sizes. Either way, identify the non-value-added steps in the process and try to remove them – certainly look to ensure they do not delay value-adding steps. The concept of pull, not push (see Chapter 1), links to your understanding the process and improving flow. And it can be an essential element in avoiding bottlenecks. Overproduction or pushing things through too early is a waste.
✔ Remove non-value-adding steps and waste. Doing so is another vital element in improving flow and performance, generally. The Japanese refer to waste as Muda; they describe two broad types and seven categories of waste. Of course, if you can prevent waste in the first place, then so much the better (see Chapters 9 and 10 on how to do this).
✔ Manage by fact and reduce variation. Managing by fact, using accurate data, helps you avoid jumping to conclusions and solutions. You need the facts! And that means measuring the right things in the right way. Data collection is a process and needs to be managed accordingly. Using control charts (Chapter 7 has more on these) enables you to interpret the data correctly and understand the process variation. You then know when to take action and when not to.
✔ Involve and equip the people in the process. You need to involve the people in the process, equipping them to both feel and be able to challenge and improve their processes and the way they work. Involving people is what has to be done if organisations are to be truly effective, but, like so many of the Lean Six Sigma principles, it requires different thinking if it’s to happen. (See Chapter 18 for more on understanding the ‘people issues’.)
✔ Undertake improvement activity in a systematic way. DMAIC comes into play here: Define, Measure, Analyse, Improve and Control. One of the criticisms sometimes aimed at ‘stand-alone’ Lean is that improvement action tends not to be taken in a systematic and standard way. In Six Sigma, DMAIC is used to improve existing processes, but the framework is equally applicable to Lean and, of course, Lean Six Sigma. Where a new process needs to be designed, the DMADV method is used.
The focus in the following section is on improving existing processes with DMAIC using the appropriate tools and techniques from the Lean Six Sigma toolkit. But these tools, and the seven principles, identified earlier in this chapter also provide a framework to improve the day-to-day management and operation of processes. We look at this aspect of Lean Six Sigma, which we refer to as ‘Everyday Operational Excellence’, in Chapter 17.
Improving Existing Processes: Introducing DMAIC
Now you can Analyse the situation by using facts and data to determine the root cause(s) of the problem that’s inhibiting your performance. With the root cause identified, you can now move to the Improve phase, identifying potential solutions, selecting the most suitable, and testing or piloting it to validate your approach, using data where appropriate. You’re then ready to implement the solution in the Control phase.
The Control phase is especially important. You need to implement your solution, checking that your customers feel the difference in your performance. You’ll need to use data to determine the extent of the improvement and to help you hold the gains. After all your