“Since President Obama took office, there are over 450,000 more unemployed women.”

A new ad from Mitt Romney’s campaign uses small-business owner Melanie McNamara to make the case that Obama hasn’t helped the economy — particularly for women.

“He promised to bring us all together, that we’re all going to be able to prosper,” she says in the ad. “I don’t see the prospering.”

She voted for him 2008 but won’t this time, she says.

An on-screen visual says, “Since President Obama took office, there are over 450,000 more unemployed women.”

In exploring whether that number is accurate, we should note that economists say raw numbers are problematic because the population grows over time and the desire to join the labor force can wax and wane for reasons beyond broad economic conditions.

In examining the Romney campaign’s claim, we find the numbers can be tallied different ways to tell two very different stories.

The outcome depends on when you start counting. If you start in January 2009, the month that Obama took office, there has been a 451,000 increase in the number of unemployed women 16 and up through the latest report, which was issued last week.

But start the count later and you get a much different picture. The Obama campaign often uses February 2010, which was the point when monthly job changes turned from negative to positive.

The problem is, each party’s approach amounts to cherry picking. Starting the count on the day Obama was sworn in ignores the reality that no president can have much impact on the economy in their first weeks or even months on the job — a point that’s particularly important in Obama’s case because the job numbers were in a virtual free fall when he began his term on January 2009. On the other hand, starting the count at the low point, one year after taking office, shields Obama from any responsibility for more than a year.

We’ve often taken a middle ground, starting the count in June 2009, which was the official start of the recovery, and a few months after Obama’s stimulus law took effect.

As it turns out, using June 2009 makes a major difference in the result. Between June 2009 and September 2012, the number of unemployed women actually decreased by 548,000.

There’s also another way to look at it — to compare the 44 months after January 2009 to the 44 months prior to January 2009. During this period — the final 44 months of George W. Bush’s presidency — the number of unemployed women rose by almost 1.4 million. That’s more than triple the increase in unemployed women that we found even under the least flattering measurement for Obama.

And if you look at Bush’s entire eight-year term, the number of unemployed women rose by more than 2.2 million. Even accounting for Bush’s longer tenure, that’s a rise far more rapid than occurred under Obama.

Our ruling

The Romney campaign claimed that “since President Obama took office, there are over 450,000 more unemployed women.”

That’s literally true, but the statistic is cherry-picked. Starting the count at the beginning of the recovery, rather than the beginning of Obama’s term, produces a starkly different result — a decrease of 548,000 unemployed women. And the rise in women’s unemployment under Obama pales compared to the rise experienced under George W. Bush. These important pieces of context are left out of the ad. On balance, we rate the claim Half True.