The wealthiest philanthropists say they want to push for social change, but most of their largest donations are going to institutions such as universities, hospitals and cultural organizations, according to a new study by The Bridgespan Group.

Eighty percent of major donors say they want their large gifts to facilitate social change, but only 20 percent of their donations of $10 million or more go to causes such as reducing genocide, reforming criminal justice, eliminating disparities in health care and other social issues, according to the study.

The Bridgespan Group, a nonprofit consultant and resource for mission oriented organizations and philanthropists based in Boston,  studied the public mission statements of 100 major donors and reported the findings in "Making Big Bets for Social Change," which was published in the Stanford Social Innovation Review.

Bridgespan says there is an "aspiration gap" between what major donors say they would like to achieve and where they direct their largest gifts.

"There is no shortage of generosity in American philanthropy, which is to be celebrated," said William Foster, head of the consulting practice at The Bridgespan Group and co-author of the report. "But the gap between philanthropists' social-change goals and the direction of actual giving is striking."

Giving large donations to organizations that promote social change—many of which are small and don't have the capacity to easily absorb a large gift—is more difficult than giving to  established universities, hospitals or cultural organizations, which have well-organized fund-raising arms, Bridgespan said. In addition, the results are usually easily visible when gifts are given to large institutions.

“Another inhibitor is networks. Whereas university alumni have a built-in relationship to their alma mater, personal relationships between philanthropists and non-profit leaders can take years of hard work to nurture,” said Bridgespan.

"Funding social change takes a different mindset," said Chris Addy, Bridgespan partner and co-author of the report. "Philanthropists who do make successful big bets on social change have often approached their philanthropy more like venture capital, investing significant time and effort in finding the 'deal' and knowing that not all big bets pay off. They move beyond an institutional mindset, rediscover their audacity and embrace risk by making big bets."

Bridgespan cites examples of large donations to small organizations that paid off, such as a $15 million gift from Gap Inc. founders Don and Doris Fisher to the Knowledge is Power Program. Through the gift, Knowledge Is Power grew from two charter schools to 183 schools that serve 70,000 students nationwide.

Another example is the John D. and Catherine T. MacArthur Foundation’s decision to focus its resources on combating climate change and reforming the criminal justice system, Large successful donations spur other philanthropists to act, the study said.