Why is trial and error often necessary in human-factors engineering design?

In human-factors engineering—a field closely related to bioengineering—trial and error is often necessary because the pace of technological innovation outstrips the accumulation of behavioral data.12

While the field strives to replace intuition with the scientific method, engineers frequently design novel machines and environments faster than behavioral scientists can study how humans will respond to them. Because there are more emerging design problems than there are established, theoretical answers, human-factors specialists are often forced to rely on empirical testing to identify and resolve human-machine mismatches. Consequently, although the goal is to apply rigorous data regarding human behavior, the specific techniques employed in practice are typically empirical rather than purely theoretical.1