When it comes to high-end strategic advice, McKinsey is the gold standard.  But opining on what good strategy looks like is not sufficient to explain the remarkable, and enduring, ubiquity of bad strategy—even, it must be said, among McKinsey clients.

What, then, explains why the Best & Brightest, with an inexhaustible supply of MBA's at their disposal, so often bollix it up?  To begin with, "the basic assumption of modern economics—rationality—does not stack up against the evidence."

It's a long article, but if your firm is contemplating any strategic departures, read it and read it again.