Our problem is a complex one. It is framed by the wider question of how the general wage and salary structure of in­ dustry is arrived at. It requires a definition of work. It in­ cludes the problem of how to assess the ability of people so as to ensure that they have jobs appropriate to that ability. And it calls for principles that can provide for stability in the arrangements made, while at the same time making due allowance for the changes that occur in people and the changes occuring in the work that has to be done.