A promising demonstration can conceal an expensive weakness. A battery may perform well in a laboratory yet deteriorate too quickly in a cold British winter. A new control system may work perfectly on a test rig but fail when fitted to ageing equipment, operated by tired people, or supplied with incomplete data. This is why how engineers assess technology risk is rather different from judging whether a technology is fashionable, well-funded or impressive at an exhibition.
The central question is not simply, ‘Does it work?’ It is, ‘Will it continue to work safely, economically and predictably in the conditions for which it is being bought?’ Engineers learn early that a sound answer requires evidence, scepticism and an understanding of the whole system. It also requires a willingness to say that the evidence is not yet sufficient.