The most important finding from a new study on paternity leave is probably also the least surprising: New dads tend to take off the exact amount of time they’ll get paid to take.

Boston College’s Center for Work and Family released its annual study last week.

This year, it focused on paternity leave: how much leave fathers take, how important the benefit is to new dads and how much paid time off they receive after the birth of a child.

The study, said Brad Harrington, the center’s executive director and a professor at Boston College’s Carroll School of Management, found a strong correlation between how much paid paternity leave men receive as an employee benefit and the length of time off they took.

For instance, among respondents who received two weeks of paid leave, the largest share of those fathers (64 percent) took off two weeks. The same went for those who got one week of paid leave (34 percent, the largest group, took one week), as well as those who got four weeks of paid leave (41 percent, again the largest share, took off the full four weeks).

Most respondents – 86 percent – said they wouldn’t use paternity leave or parental leave unless they were paid at least 70 percent of their salaries; 45 percent said they wouldn’t use it unless they received their pay in full.

The decision is probably economic, as many of these fathers may be the main breadwinner. Yet the figures are also telling about the cultural norms around paternity leave in the U.S., one of the few developed economies that does not offer statutory paid leave. Most fathers are allowed to take 12 weeks of unpaid leave through the Family and Medical Leave Act if they have been in their jobs for a year, but paid leave is at employer discretion.

While some companies, particularly in Silicon Valley, offer generous benefits for fathers – Facebook gives new dads four months of paid leave; at Yahoo, it’s eight weeks – just 14 percent of U.S. employers offer paid leave for new dads at all.

The Boston College research, meanwhile, surveyed 1,029 fathers who work at 286 organizations. Harrington noted that 58 percent of respondents came from nine companies that are part of CWF’s member network, which he said means they tend to have a more progressive approach to employee benefits than other firms do. They also employ highly educated, salaried professionals who may be more apt to use the benefit.

Even so, the majority (64 percent) of dads still took only between one and two weeks off after the birth of a child. And they cited workplace stigmas against men who take paternity leave.

“There is still the expectation in many minds that taking more than a week would not be appropriate,” Harrington said.