Henry Petroski

“You can almost say that a design error is a human error because, after all, it's we humans who do the designing.”

“It seems to be a law of design that for every advantage introduced through redesign, there is an accompanying unintended disadvantage.”

“No design, no matter how common or seemingly insignificant, is without its adamant critics as well as its ardent admirers.”

“We call the fates of the Titanic and the Concordia - as well as those of the space shuttles Challenger and Columbia - 'accidents.' Foreseeing such undesirable events is what engineers are expected to do. However, design trade-offs leave technological systems open to failings once predicted, but later forgotten.”

“Failures are much more dramatic than successes, and people like drama. I think this is why automobile races draw such crowds. People expect spectacular crashes, which we tend to find more interesting than cars just racing around the track. The same is true of bridges, buildings, or any structure or machine.”

“Any design, whether it's for a ship or an airplane, must be done in anticipation of potential failures.”

“Successful design is not the achievement of perfection but the minimization and accommodation of imperfection.”

“All conventional wisdom has an element of truth to it, but good design requires more than an element of truth - it requires an ensemble of correct assumptions and valid calculations.”

“I employ case studies of failure into my courses, emphasizing that they teach us much more than studies of success. It is not that success stories cannot serve as models of good design or as exemplars of creative engineering. They can do that, but they cannot teach us how close to failure they are.”

“Case studies of failure should be made a part of the vocabulary of every engineer so that he or she can recall or recite them when something in a new design or design process is suggestive of what went wrong in the case study.”

“I was always told that I was good in mathematics, and I guess my grades and standardized test scores supported that. My worst subjects were those that generally involved a lot of reading - English and history. So, having good test scores in math and mediocre ones in reading, I was naturally advised to major in engineering in college.”

“Because every design must satisfy competing objectives, there necessarily has to be compromise among, if not the complete exclusion of, some of those objectives, in order to meet what are considered the more important of them.”

“The paradox is that when we model future designs on past successes, we are inviting failure down the line; when we take into account past failures and anticipate potential new ways in which failure can occur, we are more likely to produce successful designs.”

“Many new technologies come with a promise to change the world, but the world refuses to cooperate.”

“Everything we do is designed, whether we're producing a magazine, a website, or a bridge. Design is really the creative invention that designs everything.”

“Engineering is achieving function while avoiding failure.”

“Failure is central to engineering. Every single calculation that an engineer makes is a failure calculation. Successful engineering is all about understanding how things break or fail.”

“I emphasize that virtually every engineering calculation is ultimately a failure calculation, because without a failure criterion against which to measure the calculated result, it is a meaningless number.”

“Too much redesign has to do more with fad and fashion than with fitness and function. It is change for the sake of change. Such redesign is not only unnecessary, it is all too often also retrogressive, leading to things that work less effectively than those they were designed to replace.”

“I'm a firm believer that no matter how small an object is, you can find interesting things out about it and its history.”

“Design is nothing if not decision making.”