Below are some extracts, you can read more here
"The UK’s Cranfield University has been cranking out reports about women on British boards for the past 19 years and the one it did in 2010 had five key recommendations including this one: “Advertise all non-executive director positions in the private sector.” The reaction in UK boardrooms was “quite vehement”, one of the report’s authors told me last week. “We academics were told we didn’t know what we were talking about,” said Ruth Sealy, a management professor at the University of Exeter."
"I still think a lot more board jobs could be advertised openly. Picking someone for a role as important as this is surely worth some bother. And I do not believe the pool of suitable candidates is nearly as small or indifferent as some CEOs claim."