I'll say it again: Execution! It's always been the No. 1 reason why CEOs fail, as my colleague Geoff Colvin and management guru Ram Charan have preached over the past decade. But particularly right now, as growth is so hard to come by and countless bosses are blowing it, there's a rising appreciation of this most critical thing.

At least among the really smart bosses. I noticed it at last week's Yale CEO Summit, where the discussions were off the record -- but I got approval to share a few highlights with you. In a breakout session, Boeing chief Jim McNerney said, "Figuring out where you're going to go -- that's easy. It's necessary but not sufficient. Execution is the thing." McNerney. "Most people would choose an idea 70% as good that can be executed over an idea that's 100%. Every time. And it's important to ask, who is going to execute with you?"

Verizon CEO Ivan Seidenberg agreed. "We put every strategic idea through the execution lens," he said during the small-group discussion. "If you can't show us how you're going to do something, you get booed by the room."

Speaking of getting booed, an IBM VP of corporate strategy, Anil Menon, detailed the rigors of pitching a plan to IBM chief executive Sam Palmisano: "What if I approve it right now?" Palmisano asked Menon upon hearing one such proposal. "What will you start doing different on Monday morning?" Menon recalled Pamisano drilling him this way: "What resources do you recommend I move? Who will move those resources from what to what segment? How much where? Who will be accountable for the actions implied in this strategy?"

"I'll have to get back to you," Menon told Palmisano.

"OK, then it's a bullshit strategy," replied the IBM chief.

Classic Palmisano, says Menon, who was ejected from the CEO's private conference room. "It was a coaching moment that Sam used on me," he says. "By the way, what he did with me, I see him doing it all the time in the strategy team when different strategies are brought forward."

Is it any wonder that IBM (IBM) is one of the best-performing stocks on the Dow year to date? (And isn't it stunning that an 18% share-price decline is "best-performing"?) Verizon (VZ) shares are significantly beating the Dow too. Meanwhile, a downdraft from plane delays and union problems has sunk Boeing (BA) 55%, but investors seem to be keeping the faith in McNerney, who earned his chops at Procter & Gamble (PG), General Electric (GE), and 3M.

By the way, it wasn't lost on anybody at last week's CEO Summit that one other boss who swung by to accept the "Legend in Leadership Award," JPMorgan Chase (JPM) chief Jamie Dimon, happens to be a maniac on details. Dimon got lauded for that. And as I wrote in Jamie Dimon: No bonuses for you!, he's the standout survivor in banking.