From the article:

The William and Flora Hewlett Foundation’s Guiding Principles state that the foundation “focuses on the most serious problems facing society where risk capital, responsibly invested, may make a difference over time.” The foundation’s grantmaking strategies, with goals ranging from mitigating climate change to reforming California’s fiscal policies, reflect the board’s and staff’s considerable tolerance for risk. This article outlines our framework for investing in strategies where the likelihood of success is small and often difficult to quantify….