The federal family leave law guaranteed new mothers and fathers working for larger employers unpaid maternity leave after the birth of a child. Before the law was passed, most women who returned to full-time work after childbirth went back to their old jobs. Thus the law has had a far smaller impact than originally anticipated, concludes a recent RAND Corporation study.

Researchers Jacob Alex Klerman and Arleen Leibowitz compared the employment patterns of working new mothers with those of other working women of similar age and education.

• Prior to the law's passage, 89 percent of mothers working full-time both a year before and six months after childbirth wound up working for the same employer.

• Among other full-timers, 97 percent were working for the same boss after a similar 18 month period.

• Thus, having a child appears to cause only 8 percent of mothers to switch full-time jobs.

In sum, most working new mothers seem to have held on to their jobs even before the legislation.

Source: Gene Koretz, "Did Maternity Leave Law Help?" Business Week, April 17, 2000.