Does age matter when you're CEO?

— -- Barack Obama turned 47 last week, and John McCain turns 72 on Aug. 29, which leaves voters to choose from candidates who would widely be considered too young and too old to be CEOs of the largest corporations.

Obama, born just after Alan Shepard became the first American in space, would have a hard sell to convince a board of directors at a big company that he's not unseasoned. McCain would have a tougher sell as someone so seasoned that he was born before pilot Amelia Earhart vanished trying to circumnavigate the globe.

There are some CEOs running major companies in their 40s and 70s, and those interviewed say that age has little to do with success and leadership. What matters far more, says 49-year-old Rich Templeton, who became CEO of Texas Instruments at 45, is whether executives see the heart of their career and accomplishments ahead of them or behind.

"Leaders at all ages have to be willing to hear the bad news over and over and still see a silver lining," says Leslie Gaines-Ross, a longtime CEO observer and chief reputation strategist at Weber Shandwick. She says optimism is key.

But good leaders don't turn a blind eye to the data without good reason, and the data about corporate leaders indicate that age matters a lot more than CEOs and CEO experts let on. There is a leadership sweet spot that falls in the 50s and early 60s.

The median age for an S&P 500 CEO in 2007 was 55, according to executive search firm Spencer Stuart. If anything, companies are gravitating more toward the sweet-spot age. Since 2000, the percentage of S&P 500 CEOs 50 to 59 has increased to 58% from 53%, Spencer Stuart says. Among today's S&P 500 CEOs, 27 (5.4%) are 47 and younger, and six (1.2%) are 72 and older, according to Spencer Stuart and USA TODAY research.

Energy vs. wisdom

Age is a leadership wild card as headhunters and corporate boards ponder trade-offs such as energy vs. wisdom. An experienced CEO might help a company avoid repeating mistakes, but the flexibility of youth might be important in an environment of quick adjustments.

When CEOs are hired, most talented 45-year-olds must wait their turn, and most talented 65-year-olds make way. Management consulting firm Booz & Co., which tracks departing S&P 500 CEOs, says 29% of 2,258 who left the job from 1995 through 2007 were originally promoted to the top when they were 47 or younger. Only 13 (0.6%) became CEO at 72 or older, which makes a new CEO hire at McCain's age a statistical outlier, something akin to a 41-year-old Olympic swimmer.

ForteCEO, which specializes in placing interim executives with 20-plus years of experience at struggling companies, says only 5% of them are older than 65. Mark Rittmanic, CEO of ForteCEO, says most executives of McCain's generation assumed that at 65 it was time to retire and collect a pension, and they gave little thought to working on.

A survey of 158 senior business executives by search firm CTPartners found that 47% would not hire a qualified 72-year-old as CEO. At USA TODAY's request, CTPartners followed up with a separate survey asking senior executives if they would hire a qualified 47-year-old as CEO. Of the 116 respondents, five (4%) said they would not.