Marc Epstein and Kristi Yuthas explore how nonprofits, NGOs, foundations, impact investors, or socially responsible companies can use metrics to measure the social impact of investments. They interviewed leaders at over sixty different organizations for this book. They outline a systematic approach to deciding what resources you should invest in, what problem you should address, and which activities and organizations you should support. Once you've made those decisions, you can use their tools, frameworks, and metrics to define exactly what success looks like, even for goals like reducing global warming or poverty that are extremely difficult to measure.