Buxton’s first talk, in partnership with Saul Greenberg, introduced the notion that usability evaluation can be harmful if naively done ‘by rule’ rather than ‘by thought’. Too early in the cycle and it can mute creative ideas that do not conform to current interface norms. Applied to too radical an innovation, and the many interface issues that would likely arise from an immature technology can quash what could have been an inspired vision. If done to validate an academic prototype, it may incorrectly suggest a design’s scientific worthiness rather than offer a meaningful critique of how it would be adopted and used in everyday practice. If done without regard to how cultures adopt technology over time, then today’s reluctant reactions by users will forestall tomorrow’s eager acceptance. The choice of evaluation methodology – if any – must arise from and be appropriate for the actual problem or research question under consideration.