It seems as though everyone is doing Lean these days—Lean Office, Lean Manufacturing, Lean this and Lean that. Lean is a very good process improvement methodology started by Toyota. However, Lean is frequently done without inclusion of human factors/ergonomics (HF/E). This lack of using a human centered approach lessens the effectiveness and sustainable of Lean improvements. This article will explain the reasons for that statement and help you understand that a significant amount of waste is still present after Lean has been done without regards to HF/E.
Overview of Lean
Lean is based on two pillars—continuous process improvement and respect of people (safety, environment and community). Eliminating “waste or wasteful activities” is at the heart of improvement in Lean. There are 8 “Wastes” that are evaluated in lean:
The biggest one for Ergonomics is the “Waste of Motion”. Wasted Motion impacts external and internal productivity. Lean mainly focuses on external productivity which leaves internal productivity virtually ignored. What does this mean? It means that no one is paying attention to the ability of an employee to produce more output with no increase in risk of injury or errors. The problem for Lean only practitioners is the inability to see and quantify “wastes” related to hidden human performance issues. An ergonomist looks at processes involved along with the performance and behaviors of the humans to uncover the hidden human performance “waste”. This consists of identifying and quantifying unnecessary movements, “risky” movements and cognitive processes.
Lean Levels of Waste
There are four levels of waste in Lean. In my experience, most companies stop at the first waste level because it is the quickest and easiest to do. To use the overused cliché, level 1 waste will take care of the ‘low hanging fruit’.
- Level 1—Gross waste (poor plant layout, rejects, returns, damage, dirty equipment, idle material, etc.)
- Level 2—Process and Method (poor workstation design, no maintenance, equipment issues, unsafe methods, long changeovers, etc.)
- Level 3—Microwaste (bending/reaching, excess walking, searching, no SOP, etc.)
- Level 4—“Nanowaste” (cognitive, upper extremity ergonomic risk—force, hand/wrist/finger motions, gets and grasps, etc.)
Levels 2-4 are where HF/E is definitely needed. People are the biggest source of quality, productivity and cost. Without including the human factor, the reduction and/or elimination of non-value added waste related to people will be missed. The impact to improve production, quality, reduce costs and improve health and safety will be lost. There is a direct correlation between be risk reduction and cycle time reduction, i.e. as risks are reduced (less wasted or risky motions) the cycle time is reduced (increased efficiency).
What about Six Sigma?
I feel I need to include Six Sigma into this discussion as well since it is also a common process improvement methodology that is frequently combined with Lean. The term LeanSix is becoming commonplace. Six Sigma uses a process known as DMAIC: Define, Measure, Analyze, Improve and Control. The purpose of Six Sigma is to reduce the number of defects to a six sigma level, i.e. .000001. A defect is a nonfulfillment of an intended requirement or reasonable expectation for use. There are four classifications related to defects—I will state them in relation to injuries and financial loss:
- Class 1: critical, leads directly to severe injury or catastrophic economic loss
- Class 2: Serious, leads directly to significant injury or economic loss
- Class 3: major problems with respect to intended normal use, major economic loss
- Class 4: minor problems with respect to normal use, slight economic loss
Unfortunately, it too lacks HF/E. So where does HF/E fit into Six Sigma? It all comes down to the human factor again—people can create variation in the process that can lead to slower deliver times, poor quality and increased cost. How many times have you heard (or even said), “We don’t have any ergonomic issues.” Or, “Our injury/illness rates are at or below our industry standard so we are doing fine.” Do these two statements mean all is well and that you are operating at World Class Performance, i.e. Six Sigma level? Or is there an “Iceberg” at your company where there are very few official reports of discomfort, difficult tasks or injury but there are numerous “hidden” facts and data related to human limitations that are lurking beneath the surface? Whenever I hear a company owner or manager say, “No problems here” I tend to think s/he should be saying “No problems that I care to know of here”. There are always processes and risk factors that exist but without admitting they exist and looking for them it is easier to pretend all is fine until the ship hits the iceberg. Remember the progression of defects starts with minor (invisible), goes to major (probably still invisible) until it becomes serious to critical (visible—Iceberg!). One can use this same analogy for ergonomics—advanced ergonomics (invisible), proactive ergonomics (invisible) and reactive ergonomics (visible—Iceberg!).
In Part 2 we'll look at some lean, six sigma and ergonomics tools to show how and why all 3 combined are the best approach to achieve operational excellence.