While foundations want to help African nations, they must avoid “philanthropic colonialism,” in which projects last for only a few years and ignore local needs, said Peter Buffett, co-chair of the NoVo Foundation.

Speaking on the final day of the Global Philanthropy Forum, Mr. Buffett described how his organization has worked hard to avoid such pitfalls in the African nation of Liberia, where NoVo, the World Bank, and others are trying to rebuild the education system.

For example, in helping to set up vocational schools to teach former child soldiers, the NoVo Foundation and its partners have tried to find out what job training is relevant to the country’s marketplace.

“If you’re turning out tailors and you need plumbers, it makes no sense,” he said.

In addition, he said, to fully appreciate the challenges of working in a country recovering from war like Liberia, donors need to see the place firsthand.

“You don’t know if you don’t go,” he said.

After visiting Liberia, he said, he had a better understanding of the cultural and economic obstacles that affect his foundation’s efforts to improve education for girls. For example, female students often have responsibilities at home that keep them away from school, some families force them to get married at a young age, and a few teachers offer good grades for sex.

Finally, Mr. Buffett said working effectively in Liberia means operating closely with the government.

In response to the interest in the country by NoVo and other foundations, Ellen Johnson-Sirleaf, president of Liberia, has established a “philanthropy secretariat,” said Natty B. Davis, a Liberian diplomat.

He said the position will help make sure the foundation interest Ms. Johnson-Sirleaf has attracted will continue after she leaves office.

Mr. Buffet said that the dynamic Ms. Johnson-Sirleaf was why he first considered helping Liberia. But now having developed a close relationship with other government officials and a place in his heart for Liberians, his charitable commitment will not waver when she leaves office.

“We support her, but we support the country,” he said.