McKinsey and its peers need a new strategy. And some humility

SINCE the birth of management consultancy at the turn of the 20th century, people have questioned its usefulness. Bosses of firms that hire consultants are paid lavishly to define a vision and corral their teams into achieving it. Why would they ask a bunch of jet-setting know-it-alls who have never run anything but a spreadsheet calculation how to do their job?

Over the decades, however, consultants have proved their worth, and not just because their clients are lazy, incompetent or scared of making difficult decisions.

In 1990, McKinsey, BCG and Bain, the three elite strategy advisers, had a few thousand staff between them. Today they employ around 90,000. Over the past decade, their combined revenue has more than doubled. And they do seem to offer useful advice.