It is 30 years since Peter Drucker identified “knowledge worker” productivity as the biggest management challenge of the modern era. But the late, great management thinker did not distinguish between types of knowledge work. Only by doing so can managers see the true nature of the challenge – and how, by rising to it, they can exploit a new source of competitive advantage.

The conventional definition of knowledge workers as people who “think for a living” covers an extraordinary range of activities. Research scientists, foreign exchange traders, teachers, call centre operators and administrators – all are paid to think. Yet some of these jobs are routine, easy to automate and lend themselves to rules. Others, such as the highly interactive work of salespeople, lawyers and managers, are subtle, complex and difficult to codify.