WASHINGTON (AP) — Working mothers increasingly want full-time jobs, and tough economic times might be a big reason, according to a national survey.

In the Pew Research Center study being released Thursday, researchers saw a big spike in the share of working mothers who said they'd prefer to work full time; 37 percent said that was their ideal, up from 21 percent in 2007.

The poll comes amid a national debate on women in the workplace ignited by top Facebook executive Sheryl Sandberg, who writes in a new book about the need for women to be more professionally aggressive.

In "Lean In: Women, Work, and the Will to Lead," Sandberg argues that women have not made true progress in the workplace over the past decade and that they need to raise their hands more and "lean in" if they want to land more senior positions in corporate America.

The shift toward full-time work in the Pew poll, however, coincides with the recession and may have less to do with career ambitions than with financial realities.

"Women aren't necessarily evolving toward some belief or comfort level with work," says study co-author Kim Parker, an associate director at the center. "They are also reacting to outside forces and in this case, it is the economy."

Among women who said their financial situations aren't sufficient to meet basic expenses, about half said working full time was best for them. Of the women who said they live comfortably, only 31 percent said full time was their best situation.

Melody Armstrong, 34, of Hampton, N.H., works full time and says she wouldn't have it any other way.

"It works better for my family, and for our finances," Armstrong said in an interview. "It helps pay the bills and we can enjoy the lifestyle we have. We need to have two incomes."

Armstrong and her husband have six children between them, a blended family with one child off to college and a baby at home. She works for Double Black Imaging, a Colorado-based company that sells medical monitors. Armstrong says her company gives her the flexibility she needs to work her sales position from home.

"I do some work early in the morning or after dinner," Armstrong says, and can adjust around her children's school and sports schedules.

Mothers' attitudes — both for those who work outside the home and those who don't — have changed significantly. Among women with children under 18 years old, the proportion of those who say they would prefer to work full time has increased from 20 percent in 2007 to 32 percent last year.

When all adults were asked about working moms, however, just 16 percent said the best situation for a young child is to have a mother working full time. Slightly over 40 percent said part time was ideal, and one-third said staying home was best for kids.

Guiomar Ochoa, 38, of Chevy Chase, Md., has two young children and works full time. She says she'd rather work part time but says it's just not an option for her family.

"We just can't afford to not have two full-time incomes," Ochoa says. "We wouldn't be able to do it otherwise."

Ochoa, an international specialist with the National Endowment for the Arts, says she's doing her best to juggle her career and caring for her children.

"I've done a really good job of wearing my mom hat when I get home and putting everything aside as far as work goes and focusing on them," said Ochoa.

Most moms in the poll expressed confidence as parents. Nearly three-quarters of mothers with children under 18 said they were doing an excellent or very good job raising their children. Fathers were asked that question, too, and 64 percent gave themselves high marks.

Other findings in the poll:

—Roughly half of working mothers and fathers say they would rather be home with their children but work because they need the income.

—Fifty-six percent of working mothers and 50 percent of working fathers say it's either very or somewhat difficult for them to balance work and family.

—Forty percent of working mothers with children under 18 and 34 percent of working fathers say they always feel rushed.

The Pew Research findings are based on a survey of 2,511 adults nationwide conducted Nov. 28-Dec. 5, 2012. The poll has a margin of error of plus or minus 2.2 percentage points.