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.

The quote by Henry Petroski emphasizes the importance of learning from failure in the field of engineering. When he says, “Case studies of failure should be made a part of the vocabulary of every engineer,” he is highlighting the value of documenting and remembering mistakes. By studying where designs have gone wrong in the past, engineers can build a mental library of cautionary examples that guide them in avoiding similar errors in future projects.

Petroski further explains that engineers should be able to “recall or recite” these lessons when encountering new challenges. This underscores that the study of failure is not just academic but practical—it sharpens decision-making in the design process. If something in a new design reminds an engineer of a previous case study, that memory can help prevent repeating the same mistakes. In this way, failures become powerful teaching tools rather than forgotten setbacks.

The origin of this quote comes from Petroski’s lifelong work as an engineer, professor, and author, often called the "bard of engineering." His books, such as To Engineer Is Human and Design Paradigms, explore how engineering failures—from collapsed bridges to malfunctioning consumer products—can serve as critical lessons for progress. His philosophy is that studying success alone is not enough; only by confronting errors can engineers truly advance their craft.

Ultimately, Petroski’s words remind us that failure is an integral part of innovation. By embedding these lessons into the professional vocabulary of engineers, he argues that the discipline becomes stronger, safer, and more resilient. His insight encourages a cultural shift: rather than hiding or fearing mistakes, engineers should embrace them as essential building blocks of progress.