6 ideas
Mintzberg shadowed five chief executives for a week each, logging every letter, call, meeting and tour. Half their activities lasted under nine minutes and only a tenth ran past an hour. Interruptions were constant and often invited by the executives themselves.
Executives spent roughly two-thirds to four-fifths of their time in verbal contact and favoured gossip, hearsay and live calls over formal reports. Their knowledge was therefore stored in their heads rather than in documents, which made it fast to use but hard to delegate.
The classical model says managers plan, organise, coordinate and control. When actual activity was recorded, none of it could be cleanly sorted into those categories. The model states vague goals of management rather than what managers actually do with their time.
Managerial work splits into interpersonal roles (figurehead, leader, liaison), informational roles (monitor, disseminator, spokesperson) and decisional roles (entrepreneur, disturbance handler, resource allocator, negotiator). Formal authority gives the manager status, status creates contacts, and contacts supply the information that drives decisions.
Because the manager sits between the unit and outside contacts, they become the best-informed person in the unit, though not the expert on any one topic. This central position is the source of their decision-making power. It is also a trap, because passing that information on costs time the manager rarely has.
Constant interruption and a bias toward action lead managers to handle things briefly and superficially rather than reflect deeply. Read this way, the fragmented schedule is an adaptation to an open-ended job with no natural stopping point, not a personal failing. It still pushes out long-range thinking unless the manager deliberately builds structures to protect it.