Almost a year ago I wrote about how open innovation can help create a new operating system for the social sector. The piece focuses on learnings from the BridgeBuilder Challenge, a multi-challenge partnership between OpenIDEO – IDEO’s open innovation practice – and GHR Foundation to find solutions for global challenges at the intersection of peace, prosperity, and the planet. A year later, the first of three $1M BridgeBuilder Challenges is complete and the second is currently underway. In this time, we’ve learned a tremendous amount and are applying these lessons to continuously improve the program. To help guide ourselves and others in the social sector, we’ve extracted three overarching principles to guide our work and partnerships with funders in the social sector for years to come.