p.194 As part of the conceptual phase of design, the task designer needs to anticipate what might go wrong... Anticipating what might go wrong is critical to the design of cognitive tasks for complex man-machine systems.

p.195 The fine art of anticipating what might go wrong means taking sufficient time to reflect on the design to identify and acknowledge potential problems. We call this fine art requisite imagination.

p.195 Requisite imagination is the ability to imagine key aspects of the future we are planning (Westrum, 1991). Most important, it involves anticipating what might go wrong and how to test for problems when the design is developed. Requisite imagination often indicates the direction from which trouble is likely to arrive (Westrum & Adamski, 1999). It provides a means for the designer to explore those factors that can affect design outcomes in future contexts.

p.195 The failure to use requisite imagination opens the door to the threat of unanticipated outcomes. These outcomes can be incidents, accidents, or major catastrophes. Thus, successful cognitive task design involves the use of requisite imagination to avert the unwanted outcomes that seem to hide beneath the surface of all design.

p.199 Design flaws can be easy to recognize when design involves situations previously encountered. Unfortunately, with novel systems or complex designs, it is more difficult to explore completely all failure scenarios. Although engineers are encouraged to consider failure modes systematically, we know that in novel situations this may be hard to do.

p.206 Good designs come about because those involved with managing their creation think intelligently about the design process.

p.216 To achieve the desired outcome, a conceptual model should guide the designer.

p.217 Above all, the designer should have a restless mind. What situations have not been foreseen? What has been forgotten? ...Not everything can be foreseen. We must maintain a "questioning attitude."