She offered the words of advice and encouragement to members of the Women in Public Service Project, who are attending an international symposium at Bryn Mawr College outside Philadelphia.
"If women participate in their economies, the economies grow," Clinton said. "In politics, if women are not at the table ... the discussion can't be fully reflective of the needs of all the people."
Clinton launched the public service initiative in 2011 to help guide and inspire women in countries undergoing political transitions or emerging from conflicts. One of its goals is for women to hold 50 percent of public sector jobs worldwide by the year 2050.
Women can be most effective as leaders by using data and research "so that no one can dismiss or doubt the policies or proposals you will be advocating," she said.
"Good decisions are based on evidence, not ideology or preconceived notions," she said.
Clinton's audience included about 50 women from 30 countries who are taking part in the two-week gathering. Another 300 members of the local community also came to hear Clinton's remarks, according to a college spokesman.
Clinton, a former first lady and senator from New York, stepped down as head of the State Department early this year. Since then, she has been giving private speeches, writing a book and working with her family's global foundation.
Supporters are encouraging her to run again for president in 2016. She lost the Democratic nomination to Barack Obama in 2008.