Question 1

Can I actually use GOMS and Fitts's law to compare interface designs before building them?

Accepted Answer

Yes—that was the innovation. Card, Moran, and Newell introduced the Keystroke-Level Model, which lets you predict task completion time for competing designs without prototypes. This transformed interface design from opinion-based to measurable, which is why quantitative methods like A/B testing became standard practice in product work.

Question 2

Is this book still relevant if I'm working on modern interfaces—mobile, voice, AI—or is it dated?

Accepted Answer

It remains foundational. The principles underlying touch-target sizing on mobile, interaction latency budgets, and task decomposition all trace back to this work. Nearly every serious HCI curriculum still starts here because the engineering psychology framework it established hasn't been superseded—it's been extended.

Question 3

What makes this different from other design or UX books I might read?

Accepted Answer

This is a cognitive science book disguised as a design book. Rather than prescribing what interfaces should look like, Card, Moran, and Newell provide testable models for predicting how users will actually behave. That rigor is what separates this from opinion-driven design literature and why it's still the reference point for anyone serious about interface evaluation.