Slavery Index

Members of the Giving Pledge commit to give away at least half their wealth to charitable organizations and philanthropic causes. Co-founder Buffett, 82, is the world’s third-richest person, with a net worth of $56.2 billion, according to Bloomberg’s daily ranking. Gates, 57, has $68.5 billion.

An e-mail to the Bill and Melinda Gates Foundation seeking comment about Forrest’s meetings with Gates wasn’t answered.

The slavery index is being developed by a co-founder of Free the Slaves, Kevin Bales, Professor of Contemporary Slavery at the Wilberforce Institute at the University of Hull in the U.K., and Fiona David, a visiting fellow at the Centre for International and Public Law at the Australian National University. It is scheduled to debut in August, Forrest said. The Ibrahim Index of African Governance, founded by Mo Ibrahim, the Sudanese-born billionaire founder of the telecommunications company Celtel International BV, was a source of inspiration, he said.

Risk Measures

The index is based on data on slave numbers from governments, international organizations and surveys, supplemented with statistical analysis and estimation, Walk Free said in an e-mail. Measures of risk come from more than 20 global surveys of indices from groups such as the International Labour Organization, the United Nations and the World Bank.

Gates created the Seattle-based Bill and Melinda Gates Foundation to support organizations throughout the world aimed at improving education initiatives, enhancing health care and reducing poverty. Malaria, tuberculosis and polio are some of the diseases being targeted by the foundation. It was founded in 1997 and has an endowment of $36 billion.

Gates’s polio and malaria “campaigns are global campaigns, and you can actually measure it quite easily if someone has the disease,” Forrest said. “Modern-day slavery, because it’s so illegal, it’s much more difficult to measure. To get through this substantial measurement problem, we started the index.”

Nepalese Orphanage

Forrest, who founded Australia’s third-biggest iron ore producer in 2003, established Walk Free after his teenage daughter Grace volunteered in 2008 at an orphanage in Nepal and became aware of the extent of child slave trading. Seeing the condition of some of its victims prompted Forrest and his wife to act and they have so far given $260 million to the campaign and associated charities.