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In the Tenerife disaster, time and economic pressures were acting together with cultural and weather conditions. The Pan American pilots questioned their orders to taxi on the runway, but they continued anyway. The first officer of the KLM flight voiced minor objections to the captain, trying to explain that they were not yet cleared for...
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respected pilots). All in all, a major tragedy occurred due to a complex mixture of social pressures and logical explaini...
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When the water is cold, the problem is intensified because divers must then wear either wet or dry suits to keep warm, and these suits add buoyancy. Adjusting buoyancy is an important part of the
dive, so along with the weights, divers also wear air vests into which they continually add or remove air so that the body is close to neutral buoyancy. (As divers go deeper, increased water pressure compresses the air in their protective suits and lungs, so they become heavier: the divers need to add air to their vests to compensate.)
Because the weights are expensive, the divers didn’t want to release them.
In addition, if the divers released the weights and then made it back safely, they could never prove that the release of the weights was necessary, so they would feel embarrassed, creating self-induced social pressure. Our instructor was very aware of the resulting reluctance of people to take the critical step of releasing their weights when they weren’t entirely positive it was necessary. To counteract this tendency, he announced that if anyone dropped the weights for safety reasons, he
would publicly praise the diver and replace the weights at no cost to the person. This was a very persuasive atte...
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Another good example of social pressures comes from yet another airplane incident. In 1982 an Air Florida flight from National Airport, Washington, DC, crashed during takeoff into the Fourteenth Street Bridge over the Potomac River, killing seventy-eight people, including four who were on the bridge. The plane should not have taken off
because there was ice on the wings, but it had already been delayed for over an hour and a half; this and other factors, the NTSB reported, “may have predisposed the crew to hurry.”
CHECKLISTS Checklists are powerful tools, proven to increase the accuracy of behavior and to reduce error, particularly slips and memory lapses. They are especially important in situations with multiple, complex requirements, and even more so where there are interruptions. With multiple people involved in a task, it is essential that the lines of responsibility be clearly spelled out. It is
Designing an effective checklist is difficult. The design needs to be iterative, always being refined, ideally using the human-centered design principles of Chapter 6, continually adjusting the list until it covers the essential items yet is not burdensome to perform. Many people who object to checklists are actually objecting to badly designed lists: designing a checklist for a complex task is best done by professional designers in conjunction with subject matter experts.
CASE STUDY: JIDOKA—HOW TOYOTA HANDLES ERROR The Toyota automobile company has developed an extremely efficient error-reduction process for manufacturing, widely known as the Toyota Production System. Among its many key principles is a philosophy called Jidoka, which Toyota says is “roughly translated as ‘automation with a human touch.’”
If a worker notices something wrong, the worker is supposed to report it, sometimes even stopping the entire assembly line if a faulty part is about to proceed to the next station. (A special cord, called an andon, stops the assembly line and alerts the expert crew.)
“Why was that?” “Why is that the reason?” The philosophy is to ask “Why?” as many times as may be necessary to get to the root cause of the problem an...
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Poka-yoke translates as “error proofing” or “avoiding error.”
One trivial example is a device to help me remember which way to turn the key on the many doors in the apartment complex where I live. I went around with a pile of small, circular, green stick-on dots and put them on each door beside its keyhole, with the green dot indicating the direction in which the key needed to be turned: I added signifiers to the doors. Is this a major error? No. But eliminating it has proven to be convenient. (Neighbors have commented on their utility, wondering who put them there.)
Covering emergency or critical switches with a cover to prevent accidental triggering is another poka-yoke technique: this is obviously a forcing function. All the poka-yoke techniques involve a combination of the principles discussed in this book: affordances, signifiers, mapping, and constraints, and perhaps most important of all, forcing functions.
I’ve misinterpreted highway signs, as I’m sure most drivers have. My family was traveling from San Diego to Mammoth Lakes, California, a ski area about 400 miles north. As we drove, we noticed more and more signs advertising the hotels and gambling casinos of Las Vegas, Nevada. “Strange,” we
for gasoline and continued on our journey. Only later, when we tried to find a place to eat supper, did we discover that we had missed a turn nearly two hours earlier, before we had stopped for gasoline, and that we were actually on the road to Las Vegas, not the road to Mammoth. We had to backtrack the entire two-hour segment, wasting four hours of driving. It’s humorous now; it wasn’t then.
This is why the best accident analyses can take a long time to do. The investigators have to imagine themselves in the shoes of the people who were involved and consider all the information, all the training, and what the history of similar past events would have taught the operators. So, the next time a major accident occurs, ignore the initial reports from journalists, politicians, and executives who don’t have any substantive information but feel compelled to provide statements anyway. Wait until the official reports come from trusted sources. Unfortunately, this could be months or years
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My wife and I follow this convention in driving: when the driver is entering or leaving a high-speed highway, conversation ceases until the transition has been completed. Interruptions and distractions lead to errors, both mistakes and slips.
FIGURE 5.3. Reason’s Swiss Cheese Model of Accidents. Accidents usually have multiple causes, whereby had any single one of those causes not happened, the accident would not have occurred. The British accident researcher James Reason describes this through the metaphor of slices of Swiss cheese: unless the holes all line up perfectly, there will be no accident. This metaphor provides two lessons: First, do not try to find “the” cause of an accident; Second, we can decrease accidents and make systems more resilient by designing them to have extra precautions against error (more slices of
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U.S. airlines carry about two million people through the skies safely every day, which has been achieved in large part through design redundancy and layers of defense.
Design redundancy and layers of defense: that’s Swiss cheese.
One of my favorite examples in aviation is of a pilot who, after experiencing low oil-pressure readings in all three of his engines, stated that it must be an instrument failure because it was a one-in-a-million chance that the readings were true. He was right in his assessment, but unfortunately, he was the one. In the United States alone there were roughly 9 million flights in 2012. So, a one-in-a-million chance could translate into nine incidents.
Sometimes, people really are at fault.
ones we had designed the system to handle. Example: One of the people we tested requested a round-trip ticket between San Diego and San Francisco. After the system had determined the desired flight to San Francisco, it asked, “When would you like to return?” The person responded, “I would like to leave on the following Tuesday, but I have to be back before my first class at 9 AM.”
DON NORMAN’S LAW OF PRODUCT DEVELOPMENT The day a product development process starts, it is behind schedule and above budget.
There is no such thing as the average person. This poses a particular problem for the designer, who usually must come up with a single design for everyone. The designer can consult handbooks with tables that show average arm reach and seated height, how far the average person can stretch backward while seated, and how much room is needed for average hips, knees, and elbows. Physical anthropometry is what the field is called.
With data, the designer can try to meet the size requirements for almost everyone, say for the 90th, 95th, or even the 99th percentile.
THE STIGMA PROBLEM “I don’t want to go into a care facility. I’d have to be around all those old people.” (Comment by a 95-year-old man.)
Would you use a walker, wheelchair, crutches, or a cane? Many people avoid these, even though they need them, because of the negative image they cast: the stigma. Why? Years ago, a cane was fashionable: people who didn’t need them would use them anyway, twirling them, pointing with them, hiding brandy or whisky, knives or guns inside their handles. Just look at any movie depicting nineteenth-century London. Why can’t devices for those who need them be as sophisticated and fashionable today?
I remind you that although physical abilities diminish with age, many mental capacities continue to improve, especially those dependent upon an expert accumulation of experience, deep reflection, and enhanced knowledge.
As I write these words, the main problem is the discrepancy in aspect ratios. Movies come in many different aspect ratios (none of them the new standard) so when TV screens show movies, they either have to cut off part of the image or leave parts of the screen black. Why was the HDTV aspect ratio set at 16:9 (or 1.8) if no movies used that ratio? Because engineers liked it: square the old aspect ratio of 4:3 and you get the new one, 16:9. Today we are about to embark on yet another standards fight over TV. First, there is three-dimensional TV: 3-D. Then there are proposals for ultra-high
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This was good design. The door was at a school for handicapped children, and the school didn’t want the children to be able to get out to the street without an adult. Only adults were large enough to operate the two latches. Violating the rules of ease of use is just what was needed.
Here is a simple, real example. I am working with a new startup company, developing an innovative line of cooking equipment. The founders had some unique ideas, pushing the technology of cooking far ahead of anything available for homes. We did numerous field tests, built numerous prototypes, and engaged a world-class industrial designer. We modified the original product concept several times, based on early feedback from potential users and advice from industry experts. But just as we were about to commission the first production of a few hand-tooled working prototypes that could be shown to
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small self-funded company), other companies started displaying similar concepts in the trade shows. What? Did they steal the ideas? No, it’s what is called the Zeitgeist, a German word meaning “spirit of the time.” In other words, the time was ripe, the ideas were “in the air.”
In her book Different, Harvard professor Youngme Moon argues that it is this attempt to match the competition that causes all products to be the same.
before I gave up and had to consult the instruction sheet. Why did Lego believe it had to change the motorcycle? Perhaps because featuritis struck real police motorcycles, causing them to increase in size and complexity and Lego felt that its toy needed to match the world. (Photographs by the author.)
Usually it is only possible where the head of the company, the CEO, is also the founder. Once the company passes control to others, especially those who follow the traditional MBA dictum of putting profit above customer concerns, the story goes downhill.
Profits may indeed increase in the short term, but eventually the product quality deteriorates to the point where customers desert. Quality only comes about by continual focus on, and attention to, the people who matter: customers.
When one early startup company, Fingerworks, was struggling to develop an affordable, reliable touch surface that distinguished among multiple fingers, it almost quit because it was about to run out of money. Apple however, anxious to get into this market, bought Fingerworks. When it became part of Apple, its financial needs were met and Fingerworks technology became the driving force behind Apple’s new products. Today, devices controlled by gestures are everywhere, so this type of interaction seems natural and obvious, but at the time, it was neither natural nor obvious.
The world of product design offers many examples of Stigler’s law. Products are thought to be the invention of the company that most successfully capitalized upon the idea, not the company that originated it.
Ideas that are too early often fail, even if eventually others introduce them successfully.
I’ve seen this happen several times. When I first joined Apple, I watched as it released one of the very first commercial digital cameras: the Apple QuickTake. It failed.
Probably you are unaware that Apple ever made cameras. It failed because the technology was limited, the price high, and the world simply wasn’t ready to dismiss film and chemical processing of photographs. I was an adviser to a startup company that produced the world’s first digital picture frame. It failed. Once again, the technology didn’t quite support it and the product was relatively expensive. Obviously today, digital cameras and digital p...
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It took forty years for the first working videophones to be created (in the 1920s), then another ten years before the first product (in the mid-1930s, in Germany), which failed. The United States didn’t try commercial videophone service until the 1960s, thirty years after Germany; that service also failed. All sorts of ideas have been tried including dedicated videophone instruments, devices using the home television set, video conferencing with home personal computers, special video-conferencing rooms in universities and companies, and small video telephones, some of which might be worn
on the wrist. It took until the start of the twenty-first century for usage to pick up.
A rule of thumb is twenty years from first demonstrations in research laboratories to commercial product, and then a decade or two from first commercial release to widespread adoption.
Even ideas that are excellent and will eventually succeed frequently fail when first introduced. I’ve been associated with a number of products that failed upon introduction, only to be very successful later when reintroduced (by other companies), the real difference being the timing. Products that failed at first commercial introduction include the first American automobile (Duryea), the first typewriters, the first digital cameras, and the first home computers (for example, the Altair 8800 computer of 1975).
