09/20/2012 06:38 pm ET Updated Nov 20, 2012

The Obama Numbers That Really Matter: Countdown Day 47

WASHINGTON -- Bill Clinton and James Carville repeatedly have advised the Obama campaign not to brag about upbeat economic news.

"People won't believe it," said Carville, the high-profile Democratic strategist. "We knew in 1996 that it takes years for positive change to make its way out to most voters. If you start bragging, people will look at their lives and conclude 'those people in D.C. don't have a clue what's really happening out here.'"

At first glance, Carville's would seem to be sensible advice.

After all, unemployment remains above 8 percent, 23 million are out of work or underemployed, and a record 46 million Americans are mired in poverty. It turns out that some 6 million mostly middle-class voters will face a tax hike because of Obamacare -- a lot more than previously predicted.

Check any Mitt Romney speech for more numbers.

But Team Obama isn't taking the Clintonian advice. In fact, they're up with a new ad right now, touting 29 straight months of non-government job growth, even if, in some of those months, the numbers weren't impressive.

Why? For one, the economy and American society moves much faster than they did 16 years ago; 1996 is several eons in the distant past of what is now a hyper-wired society.

Bad news travels faster -- remember the speed of the global banking meltdown of 2008 -- but so does good news. And that news is more easily found by, targeted to and absorbed by opinion makers and swing voters.

The slow-motion economic recovery has varied, better in some places and sectors than in others, which means the Obama campaign can target an upbeat message of revival in those places and to those people to whom it makes sense.

A mini-revival of specialized manufacturing, not to mention the auto industry, helps the Obama administration's story in the industrial Midwest, including the swing states of Ohio and Michigan. Government and military spending have helped keep the economy relatively healthy in Virginia, where the president now leads Romney by 8 percentage points in one poll and where Democratic Senate candidate Tim Kaine is pulling ahead of Republican rival George Allen.

Timing is everything in politics, and President Obama is getting just enough verifiable positive economic news just in time to propel him into the lead against Romney on this 47th day before the election.

Reporters, campaign strategists and authors of campaign books love to dwell on dramatic tick-tick moments and tactical moves: the gaffes, grandiloquence and last-second advertising buys of the day-to-day battle. But over in academia, where things are a little less anecdotal and a lot more systematic, a growing scholarly industry is correlating macroeconomic inputs with election-year outcomes.

One of the deans of this school of thought is professor Larry Bartels, formerly of Princeton and now of Vanderbilt. He says the key statistics are "real disposable personal income growth" in the second and third quarters of the incumbent president's reelection year.

To crudely oversimplify, Bartels' formula says that an incumbent president whose party has been in office for only one term will win reelection by a comfortable margin if personal income growth is more than 1 percent in those two quarters.

According to the U.S. Bureau of Economic Analysis, personal income grew by 0.7 percent in the second quarter and by 0.3 percent in July. The August numbers aren't out yet; the story of September is, of course, unwritten. But it seems pretty clear that the president will be well over the threshold.

The growth rates are still low by the long-term historical standards of the American economy, but people -- and voters -- don't live in the long term. Psychologically, they are much more affected by things they can see right now, such as home sales and home prices. The rate of existing home sales has risen steadily since 2011; home prices have increased by one measure for the sixth straight month.

It's enough to allow Obama to stand his ground on the economy, especially given one of Bartels' other statistical theories: Presidents actually benefit in some ways from a dismal first year of their tenure -- and 2009 was truly awful. The reason is that voters tend to blame the first year on the previous president.

So that remains the most important number of all for Barack Obama: He's not the 43rd president.

For Howard Fineman's full 2012 Countdown, click here.