Jun 13 2014
for more details, you can also read about Deming’s list of “5 Deadly Diseases” in Chapter 3 of Out of the Crisis, pp. 97-148.
Jun 13 2014
for more details, you can also read about Deming’s list of “5 Deadly Diseases” in Chapter 3 of Out of the Crisis, pp. 97-148.
Mar 17 2014
The first question we usually ask about lead times, inventory levels, critical dimensions, defective rates, or any other quantity that varies, is what it is “on the average.” The second question is how much it varies, but we only ask it if we get a satisfactory answer to the first one, and we rarely do.
When asked for a lead time, people usually give answers that are either evasive like “It depends,” or weasel-worded like “Typically, three weeks.” The beauty of a “typical value” is that no such technical term exists in data mining, statistics, or probability, and therefore the assertion that it is “three weeks” is immune to any confrontation with data. If the assertion had been that it was a mean or a median, you could have tested it, but, with “typical value,” you can’t.
For example, if the person had said “The median is three weeks,” it would have had the precise meaning that 50% of the orders are delivered in less than 3 weeks, and that 50% take longer. If the 3-week figure is true, then the probability of the next 20 orders all taking longer, is . This means that, if you do observe a run of 20 orders with lead times above 3 weeks, you know the answer was wrong.
In Out of the Crisis, Deming was chiding journalists for their statistical illiteracy when, for example, they bemoaned the fact that “50% of the teachers performed beneath the median.” In the US, today, the meaning of averages and medians is taught in Middle School, but the proper use of these tools does not seem to have been assimilated by adults.
One great feature of averages is that they add up: the average of the sum of two variables is the sum of their averages. If you take two operations performed in sequence in the route of a product, and consider the average time required to go through these operations by different units of product, then the average time to go through operations 1 and 2 is the sum of the average time through operation 1 and the average time through operation 2, as is obvious from the way an average is calculated. If you have n values
the average is just
What is often forgotten is that most other statistics are not additive.
To obtain the median, first you need to sort the data so that . For each point, the sequence number then tells you how many other points are under it, which you can express as a percentage and plot as in the following example:
Graphically, you see the median as the point on the x-axis where the curve crosses 50% on the y-axis. To calculate it, if n is odd, you take the middle value
and, if n is even, you take the average of the two middle values, or
An ERP system, for example, will add operation times along a route to plan production, but the individual operation times input to the system are not averages but worst-case values, chosen so that they can reliably be achieved. The system therefore calculates the lead time for the route as the sum of extreme values at each operation, and this math is wrong because extreme values are not additive. The worst-case value for the whole route is not the sum of the worst-case values of each operation, and the result is an absurdly long lead time.
In project management, this is also the key difference between the traditional Critical Path Method (CPM) and Eli Goldratt’s Critical Chain. In CPM, task durations set by the individuals in charge of each task are set so that they can be confident of completing them. They represent a perceived worst-case value for each task, which means that the duration for the whole critical path is the sum of the worst-case values for the tasks on it. In Critical Chain, each task duration is what it is actually expected to require, with a time buffer added at the end to absorb delays and take advantage of early completions.
That medians and extreme values are not additive is experienced, if not proven, by a simple simulation in Excel. Using the formula “LOGNORM.INV(RAND(),0,1)” will give you in about a second, 5,000 instances of two highly skewed variables, X and Y, as well as their sum X+Y. On a logarithmic scale, their histograms look as follows:
And the summary statistics show the Median, Minimum and Maximum for the sum are not the sums of the values for each term:
Averages are not only additive but have many more desirable properties, so why do we ever consider medians? There are real problems with averages, when taken carelessly:
The bottom line is that you should use averages whenever you can, because you can do more with them than with the alternatives, but you shouldn’t use them blindly. Instead, you should do the following:
As Kaiser Fung would say, use your number sense.
Mar 14 2014
About two years ago, I started posting essays on this blog about Deming’s 14 points and their current relevance. Now I am writing on Points 11.a and 12 through 14, which I have not covered yet, organizing the material, and editing it into an eBook entitled The Deming Legacy, that will be available shortly in PDF, iBook and Kindle formats. If you are interested, please visit the site and let me know. Comments here are also welcome.
The posts on the topic to date are as follows:
The title is a ploy to convince Matt Damon to play Deming in the movie version.
Dec 27 2012
Organizational Sabotage – The Malpractice of Management By Objective by Ken Craddock & Kelly Allan – Innovation, quality and productivity suffer from the abuse of MBOs Objectives are essential to a business.
This article brings a new perspective on the discussion of the same topic in this blog.
Dec 16 2012
Deming’s full statement is as follows:
Eliminate slogans, exhortations, and targets for the work force asking for zero defects and new levels of productivity. Such exhortations only create adversarial relationships, as the bulk of the causes of low quality and low productivity belong to the system and thus lie beyond the power of the work force.
This point reminds me of Howie Makem, the quality cat lampooned by Ben Hamper in Rivethead in 1986, about the same time Deming’s Out of the Crisis was published. At the time, Ben Hamper was a riveter at GM’s Truck plant in Flint, MI, who could describe his shop floor experience with the wit of a Tom Wolfe. Rivethead was originally a column in Michael Moore’s Flint Voice, later edited into a book.
According to Hamper, the management of the plant had decided that what it needed to improve quality was a mascot for workers to rally around, and organized a naming contest, of which “Howie Makem” was the winning entry. The mascot then materialized as a man in a cat suit with a large Q embroidered on a red cape walking the floor and exhorting operators to improve quality amid jeers, catcalls and the occasional bolt throw. Howie Makem is one of the few artifacts of which no picture can be found on Google, which is why I had to draw it from Hamper’s description.
Spending time and money on slogans, mascots, banners and monogrammed shirts or mugs is predicated on the assumptions (1) that quality and productivity problems are primarily due to lack of motivation in shop floor operators and (2) that it can be changed by the same kind of marketing campaign that works for selling detergents. Deming’s and Hamper’s point is that it is counterproductive and that these assumptions are false.
The key points that I see about appropriate public relations and communications around Lean are as follows:
Improvement does need marketing and promotion inside the company, to customers, and to suppliers, but not at the start of the effort, and not in this form.
The beginning of an improvement program like Lean transformation is when it is most likely to fail. At that time, the organization, from management to line workers, has everything to learn about its technical and managerial content, as well as the art of implementing it. It is then that they will make the most mistakes and therefore least need publicity. The first pilot projects only need to be known and understood by those who are directly involved, and should not be announced upfront with a marching band at an all-hands meeting. You are much better off trumpeting results once the projects are successes that can inspire others. And even then, it is not done with slogans but by testimonials of participants, demonstrating the improvements directly on the floor or in video recordings.
With outsiders as well, you do it first and play it back later. You don’t announce what you are going to do, but, once it is done, you make it a field trip destination for local schoolchildren as well as other industrial tourists.
Toyota plants have visitor centers with posters on the products and cartoons explaining the production system to children and have a whole staff of professional tour guides taking groups on a set path through the plant, wearing headsets to hear the explanations. These tours are part of public relations and not given by retirees, as is the case at many other companies.
Porsche in Leipzig charges customers €1,000 extra to spend a day at the plant to pick up their Panameras or Cayennes, during which they get a tour of the shop floor featuring their version of Lean, a lunch at top of the visitor center, and an hour with a driving pro on the test track to learn how best to drive their new car in various conditions.A striking feature of this plant site, is that it is dominated by the round, inverted diamond shape of the visitor center, on the top left of the photogaph, between the test track on the left and the production shops on the right.
This is part of a new marketing trend in Germany, where, rather than hide plants away, you locate the cleanest, most automated and most spectacular processes where your customers, or even the public at large, can see them. In this spirit, Volkswagen has located a plant downtown Dresden, with glass walls for passersby to see the final assembly of cars.
Honda pioneered a different form of promotion of its manufacturing system to end users with its homecomings at the Honda motorcycle plant in Marysville, OH, where, once a year, they hosted bikers who see the production lines and meet the operators who built their bikes. The same approach was later emulated by the now defunct Saturn division of GM.
Companies in other industries rarely go this far, particularly when their products do not excite the public’s imagination. Bart Simpson’s class goes on a field trip to a box factory, which does not generate much enthusiasm.
If you make components to sell to OEMs rather than to consumers, the promotion of your Lean programs takes a different form, with customers sending teams of auditors to assess whether you are “Lean enough” to do business with, and they may send you supplier support engineers to help you implement Lean to their satisfaction. This means that you must present your plant in a way that allows the auditors to check all the marks needed to give you the right score, even if it means setting up a Potemkin village with tools that you don’t think are essential to your business.
Working with your customers’ supplier support organization — or supporting your own suppliers — is a different process, requiring a deeper level of involvement, and it is not a matter of public relations for either side, and should not be treated as one. The customer provides free consulting to help the supplier increase productivity and improve quality. In exchange, the supplier reduces prices by a fixed ratio every year, calculated so that the improvements are to economic benefit of both sides. The customer pays less, while the supplier makes more profits. It is a win-win, but not an easy system to set up and operate. It involves top management, engineering on both sides, purchasing on the customer side, and customer service on the supplier side, and it is not run by Public Relations.
Nov 28 2012
(Featured image from the Bureaucracy game, by Douglas Adams)
Deming’s complete statement of Point 9 is as follows:
“Break down barriers between departments. People in research, design, sales, and production must work as a team, to foresee problems in production and in use that may be encountered with the product or service.”
Within a large organization, it is common for departments to work at cross purposes. Each department is a functional silo, working towards goals that may be inconsistent with the interests of the whole. Deming gives many examples of disasters that occur as a consequence, and exhorts his readers to break down the barriers to keep them from happening. As with his other points, he makes no recommendation on how to accomplish this.
Let us examine several approaches that have been tried, and the issues that organizations encountered when they did:
This is not a problem for small companies. As long as the entire management team fits within a small conference room, there are few opportunities to erect barriers. In a large company where it is a problem, the most obvious solution is to organize by what is variously called business teams, business processes, value streams, or focused factories.
You dissolve the functional departments and organize multifunction teams that bring all the required talent to bear on the core activities. In a manufacturing company, for example, all the resources needed to make a family of products from start to finish — including engineers, maintenance and quality technicians, schedulers, etc. — report to one “value stream manager,” and there cannot be barriers between silos because there are no silos.
It’s like the Mission Impossible TV series, with the disguise specialist and the explosives expert working together towards a common goal, as opposed to being in separate facilities and exchanging service requests in triplicate. This is a popular picture in the US and the approach is often used in a variety of contexts, such as emergency response, as in Apollo 13, or product development, for Data General’s MV-8000 computer in 1980 in Tracy Kidder’s The Soul of a New Machine, or the 1996 Taurus at Ford in Mary Walton’s Car.
The movie Apollo 13 shows a seemingly too-good-to-be-true team that is thrown together to find a way to fit the square connector of the command module air scrubber to the round hole used on the lunar module, using nothing but the odds and ends available to the astronauts on the crippled spacecraft. But the story is true, and we have a picture of the actual device the astronauts built.
This was the philosophy of Business Process Reengineering (BPR). Each business was to be broken down into processes turning some input into an externally visible output. Manufacturing, in BPR, did not qualify as a process. Instead, it was subsumed into the order-fulfillment process.
But it is not a panacea. The development of the 1996 Taurus took 30 months, and it was a major improvement over previous products at Ford, but still not down to the 24 months used at Toyota for the Rav4, and Toyota uses a traditional structure with functional departments communicating through memos.
In addition, according to Mary Walton, Ford’s integrated, collocated team made design decisions that made manufacturing more difficult. She explains in particular that the sculptured shape of the side panels made them more difficult to stamp, and this happened even though manufacturing was represented in the team. As a work of art, the 1996 Taurus was stunning. As a commercial product, however, it was lackluster, losing the previous versions’ bestseller status in the US market to the more “boring” Honda Accord and Toyota Camry in 1997.
The reality is that organization structure does not determine outcomes. The caliber of the individuals, their motivations for the roles they are playing, and their interaction protocols are at least as important. In their July, 1998 Harvard Business Review article , D.K.Sobek, J. Liker, and A.C. Ward listed the following practices as key to Toyota’s performance in product development:
The Toyota example is about product development. But what about other activities like operations? When you attempt to organize everything by business process, or by value stream, in most cases you encounter some functional departments that you technically cannot or should not break up.
Most machine shops have a central heat treatment facility. Induction hardening can, for some work, distribute heat treatment among different production lines and break down the “heat treat silo,” but a given shop may make products to which it is not applicable, its customers may not approve the process, or it may not have the skills or resources to implement it. Electroplating and painting commonly are similar challenges. As a result, the plant ends up with a few common services organized as functional departments along with lines that take a family of products through a sequence of operations.
Among support functions, the picture is also mixed. Production scheduling at the detailed level, for example, works better when the schedulers work directly for the manager of a production line than in a central department, because local scheduling is a simpler problem and the relevant specifics of machine behaviors are more accessible. On the other hand, breaking down a maintenance department and making the technicians report to production managers may not enhance their responsiveness when, for example, the group assigned to a line is short of the critical mass needed to have at least one technician standing by for the next emergency.
Other departments remain organized centrally because of the information they have access to, like Human Resources, Accounting, or Technical Data Management; others, because of external entities they deal with, like Shipping and Receiving.
When breaking down a functional department and reassigning its members to teams organized around processes, we also need to consider how it affects the people to whom we do it. Professionals like medical doctors or lawyers work for clients who have little or no knowledge of their specialties, but it is then up to them to decide how much of their revenue to spend or maintaining their skills. They choose which magazines tp subscribe to and which conferences to attend, without asking anybody’s permission.
An engineer reporting to a production manager also works for one “client” who does not have the same expertise, but as an employee. If this engineer wants to attend a conference, the first step is to get approval for the time and money it will consume, from a manager with no knowledge of whether it is a good idea.
In the long term, what career does this engineer have to look forward to? The manager needs the engineer’s skills here and now but is ill equipped to provide guidance, compared to an engineering manager whose background and experience are in the same field.
For this reason, some companies have adopted matrix organizations, in which specialists report “solid-line” to a process owner who needs their skills in operations or on projects, and “dotted-line” to a functional manager for skills maintenance and career development. In a diagram, as follows, this structure looks simple and attractive:In reality, of course, it is a more complex form of organization than a simple hierarchy, and conducive to all sorts of tensions regarding authority and responsibility.
Project work — like product development, new product introduction, or new plant setup — differs from operations in that it ends when a goal is reached, which may be a working prototype, a target takt time in production for the new product, or for the new plant. At that point, the teams are disbanded and their members move on.
This is a particularly sensitive transition to manage when you collocate a multifunction project team in one big room, because its members bond both with the project and with each other, and receive the ending like a psychological blow on the scale of the loss of a family member. This is another reason why they need to retain a connection with their functional peers.
Breaking down barriers between departments for the greater good of the organization as a whole is a worthy goal, that high-level managers have been pursuing since, at least, the Roman empire. There is no simple recipe. The approaches followed by successful organizations have been subtle, nuanced, and fitted to their purposes.