Whose Measurement is Right?
Every company I’ve worked for inspects the product it receives from its suppliers to determine conformance to requirements. The process is variously referred to as incoming inspection or receiving inspection.
Sometimes the receiving inspection process identifies a lot of product that fails to conform to requirements. That lot is subsequently classified as nonconforming material and quarantined for further review. There are many reasons why a lot of product may be classified as nonconforming. Here I wish to focus just on reasons having to do with measurement.
Once a company discovers nonconforming parts, it usually contacts its supplier to share that information. It is not unusual, however, for the supplier to push back when their data for the lot of product shows it to be conforming. So, how can a given lot of product be both conforming and nonconforming? Who is right?
We need to recognize that measurement is a process. The measured value is an outcome of this process. It depends on the measurement tool used, the skill of the person making the measurement and the steps of the measurement operation. A difference in any of these factors will show up as a difference in the measured value.
It is rare that a measurement process is the same between a customer and its supplier. A customer may use different measurement tools than its supplier. For example, where the customer might have used a caliper or micrometer, the supplier may have used an optical comparator or CMM. Even if both the customer and the supplier use the same measurement tool, the workers using that tool are unlikely to have been trained in its use in the same way. Finally, the steps used to make the measurement, such as fixturing, lighting and handling the part, which often depend on the measurement tool used, will likely be different, too.
Thus, more often than not, a measurement process between a supplier and a customer will be different. Each measured value is correct in its context—the supplier’s measurement is correct in its context, as is the customer’s measurement in its context. But because the measurement process is different between the two contexts, the measured values cannot be compared directly with one another. So it is possible that the same lot of product may be conforming per the supplier’s measurements and nonconforming per the customer’s measurements.
But why are we measuring product twice: once by the supplier and again by the customer? Measurement is a costly non-value adding operation, and doing it twice is excess processing–wasteful. One reason I’ve been told is this is done to confirm the data provided by the supplier. But confirmation is possible only if the measurement process used by the customer matches the one used by the supplier.
Besides, if we are worried about the quality of supplier data, we should then focus efforts on deeply understanding their measurement process, monitoring its stability and capability, and working with the supplier to improve it if necessary. With that we should trust the measurement data the supplier provides and base our decisions on it, and eliminate the duplicate measurement step during receiving inspection.
Links
[1] Eliminate Waste in Incoming Inspection: 10 ideas of where to look for waste in your process http://www.qualitymag.com/articles/92832-eliminate-waste-in-incoming-inspection Retrieved 2017-06-29
Above All, Don’t Wobble
In walking, just walk. In sitting, just sit. Above all, don’t wobble.
– Yúnmén
The companies I’ve worked for have been neurotic. They dither. When decisions are made they have an irrational and anxious quality about them.
My experience of work can be described as a shuddering paralysis. In an effort to take everything into account teams I’ve been on enter into an infinite regression of analysis that often takes us off course, delaying action. (I have been guilty of contributing to this.) However, the essence of a business is to act, to do.
When we do act, we don’t just act, but worry about whether that action is the best possible; we complain about all the flaws we find in the method; we even wonder whether the goal is the right goal. So our attention is split, bouncing between acting and thinking. Instead of moving gracefully toward our goal, we wobble. I wobble.
Perhaps Yúnmén wouldn’t mind if I rephrased his quote as “In planning, just plan. In doing, just do. Above all, don’t wobble.”
Retraining Can’t Fix This
In the course of an average workday we make hundreds of decisions. Some of those decisions require engaging our conscious awareness. In my previous post I described how the quality of those decisions deteriorate as that awareness or willpower fatigues with use.
However, there are decisions where human error occurs with certainty even if our attention is totally focused on the task. Consider the Muller-Lyer[1] illusion below:
The two vertical lines are of the same length. Even after knowing this, we all continue to perceive the line on the left to be longer than the line on the right. The “fact” that the two lines are of different lengths is simply obvious to us. Because of its obviousness we don’t stop to check our judgment before acting on it. Such actions, based on erroneous perception, are likely to produce faulty outcomes.
This error in our human perception/cognition system is hard-wired into our brains. No amount of retraining or conscious effort will correct it. So corrective actions that identify retraining as the way to prevent recurrence of this type of error won’t be effective. It will only serve to demoralize the worker. What, then, is an effective corrective action for such errors?
We can develop and use tools and methods that circumvent the brain’s perception/cognition system, for example with an overlay (red lines in the figure below), or actually measuring each line and comparing those values to one another. This does add a step to the evaluation process; an after-the-fact fix to a faulty design. Ideally, though, we would want our designs to take into account human limitations and avoid creating such illusions in the first place.
Links
[1] Muller-Lyer illusion https://en.wikipedia.org/wiki/Muller-Lyer_illusion Retrieved 2017-06-22
Human Error
Often, investigators identify the root cause of a problem as human error. But what exactly is human error?
An action may be judged as an error only in relation to a reference or standard. So first a standard on how to perform the task must exist. Sometimes such a standard is defined in a documented procedure. On occasion it may also be taught by a master to an apprentice on the job. Most times we just figure it out through a combination of past experience, current observations, and some fiddling. Human error, then, is action by a human that deviates from the standard.
When we judge the root cause of a problem as human error we’re making certain assumptions: 1] that a standard exists, and 2] the standard, if it exists, is adequate to the degree that mindfully following it produces the expected outcome.
Let’s grant that both the above assumptions are true, and even grant that the root cause of a problem was the failure of the worker to follow the standard. What, then, should the corrective action be that will prevent the recurrence of the problem? In my experience it has almost always been defined as “retraining”. But such a corrective action assumes that the worker failed to follow the standard because they don’t know it. Is this true? If not, retraining is pure waste and won’t do a damn thing to prevent the recurrence of the problem.
If a proper standard exists and the worker has been trained to it, then there must be some other reason for their failure to follow it. Skill-based errors (i.e. slips and lapses) can occur when the worker is unable to pay attention to or focus on performing the task they are otherwise familiar with. So it’s not a training issue. In my previous post I wrote about how willpower, our conscious awareness, is like a muscle. It can fatigue from use. As willpower is depleted the mind resorts to mental shortcuts or habits. This is how errors creep in.
We should not rely only on our ability to remain attentive and focused to ensure that the task is performed without failure. For that we must design tasks in such a way that failure is unlikely, if not impossible, to occur. Through design thinking we can develop tools, methods, and systems that help us perform better.
Links
[1] Understanding human failure. http://www.hse.gov.uk/construction/lwit/assets/downloads/human-failure.pdf Retrieved 2017-06-15
Personal Willpower, Communal Impact
We seem to make decisions in more impulsive ways than before. Many of us don’t seem to practice any reasonable amount of self-control. I feel this may be because most of us today just don’t have strong willpower.
Last year I read a book called “Willpower”[1] by Roy F. Baumeister and John Tierney. In it the authors liken willpower to muscle. And just like a muscle willpower can wear out from fatigue. When willpower is worn out, we behave more impulsively. How quickly we drain our willpower depends on how strong it is.
In using our willpower to make decisions we’re using our conscious mind or “System 2” as Daniel Kahneman refers to it in “Thinking, Fast and Slow”[2]. Conscious decision making or thinking is hard! It requires effort and uses a lot of energy in the process.
The body, however, has a limited store of energy. When we are low on energy, this conscious decision making process shuts down and decision making is shunted to the brain’s default decision making process or “System 1.” It doesn’t require much energy; it’s automatic and occurs outside of our conscious awareness. Many of the decisions we make in the default mode are driven by habit.
Conscious decision making generally produces reliable outcomes. We make better decisions with it. Not so with automatic decision making, which has been shown to be error-prone, often in systematic ways. So it’s important that we exercise our willpower; build it up, and make it stronger.
No one can make you exercise your body or mind. That’s a choice you make for yourself. But the results of your choice affects your behavior which in turn affects society. We live in communities and we have an obligation to them: to be the best version of ourselves.
Links
[1] Baumeister, Roy F., John Tierney (2012). Willpower: Rediscovering the Greatest Human Strength.
[2] Kahneman, Daniel (2011). Thinking, Fast and Slow.
The Context for Concepts
In my last post I might have left the impression that conceptualizing the real place is bad or that we should avoid it. This is not a correct impression.
We cannot avoid conceptualizing the real place. It’s automatic; part of our biological structure and the structure of our language. Concepts are how we make sense of the real place. They provide insights into the real place. We need those insights to respond appropriately to the real place. But we shouldn’t lose sight of the fact that concepts are the mind’s representations of the real place and not the real place itself! We can call them images, idols, models, data, or symbols.
D. T. Suzuki[1] shared, “To point at the moon a finger is needed, but woe to those who take the finger for the moon…” Alfred Korzybski[2] wrote in Science and Sanity, “A map is not the territory it represents, but, if correct, it has a similar structure to the territory, which accounts for its usefulness.” George E. P. Box[3], in Statistics for Experimenters, put it pithily that “all models are wrong; some models are useful.” These reminders, to be consciously aware of the difference between the real place and our mind’s abstractions of it, is the thread that runs through science and religion.
Problems only arise when we hold onto a concept long after it has stopped representing the real place and a gap has developed between what is and what we conceptualize it to be. To know what is, we must first “go and see” the real place. Without that direct experience with the real place, we cannot hope to act in ways appropriate to it. This is my understanding of what Zen and lean teach.
Links
[1] D.T. Suzuki
[2] Alfred Korzybski
[3] George E.P. Box
The Real Place
My study of Buddhist thought, and especially Zen, have so far taught me that I am often unaware of the real place. Decades of schooling and acculturation to society have taught me to ignore the real place in favor of concepts manufactured by the human mind; to create and be hypnotized by images and models. Right, wrong, god, devil, me, you, husband, wife, mother, father, boss, servant, friend, enemy, success, failure, good, bad, us, and them are all concepts. These are all creations of the mind. It gives them meaning. They’re not real.
Concepts are static–unchanging and easy to grab a hold of and cling to, while the real place is dynamic–ever changing; sometimes in predictable ways, most times in unpredictable ways. The real place offers nothing to grab on to; nothing to cling to. It is inevitable then that the two will eventually diverge from one another. I believe that that gap between what I see and what I think I see is the source of much, if not all, my suffering–frustration, anxiety, feelings of helplessness, exhaustion, and such. To experience the real place, I must let go of concepts, or rather I should not cling to them. Only then will my actions be appropriate or right for the real place.
Zen has been useful in ferrying me back to the real place every time my mind drifts to concepts.
My most direct experience of this gap, or at least one that I am most aware of, has been in the workplace. Data, charts, procedures, policies, concepts abound. Again, most, if not all, are disconnected from the real processes and systems. How work actually happens. However, like me, organizations remain mostly unaware of the disconnect. They thus suffer in a mire of internal conflict and frustration, too.
Lean can be useful to get organizations back to the real place.
Iterations 