by Matthew Syed, BBC News
When the Central Intelligence Agency (CIA) failed to prevent the September 11, 2001 attacks, many asked whether more could have been done. But the true reason why the agency was blind to the signs may be a diversity problem, writes Matthew Syed.
The failure of the CIA to spot the warning signs of the 9/11 plot has become one of the most hotly contested issues in the history of intelligence. There have been commissions, reviews, internal investigations and more.
On the one side are those who say that the CIA missed obvious warning signs. On the other are those who argue that it is notoriously difficult to identity threats in advance, and that the CIA did everything they reasonably could.
But what if both sides are wrong? What if the true reason why the CIA failed to detect the plot is more subtle than either side has realized? And what if this problem extends beyond intelligence and silently afflicts thousands of organisations, governments and teams today?