η = Work output/ Work input x 100%?

For those with a more empirical bent of mind than is fashionable these days, efficiency is defined as the ratio of useful output energy to the total input energy of a device: η = work output/work input x 100%. As may be noted by people who still believe in the laws of physics, increasing input alone doesn't guarantee more efficiency. But it certainly can be a criterion, tech-leveraged input included. Unlike physics, though, human psychology, especially of the Warren Hastings-Gordon Gekko variety, see it all being about maximising output while minimising input. But push psychology over the edge of natural laws and you have productivity machines running on fumes.

Take multitasking. Once heralded as the pinnacle of efficiency, it's clear that one person juggling the tasks of five usually results in doing none of them well. Yet, the myth persists. This is largely because people stricken with 'smarties' think it's far easier to tweak the definition of 'well' in the context of doing a job. And partly because a new business model is all the rage: make money by not spending. Management gurus are still trying to find the El Dorado of efficientiam maximas: building a penthouse without wasting money on a ground floor. And let's not forget meetings - the time vortex where efficiency goes to die. But what do physical laws know about human ingenuity, eh?