A few years ago, Acumen, a patient capital impact investment firm, developed a method for measuring impact called Lean Data. The method uses mobile technology to interact with low-income customers of impact enterprises, to learn directly from them how they experience the product or service in question. This involved experimenting with a variety of approaches but, in the process, they realized that enterprises in the Acumen portfolio interacted with their customers all the time and they could leverage all those interactions to gather data and build new metrics. Instead of creating top down benchmarks, they would allow customers to describe how the product or service had affected their lives. Ultimately, they developed surveys for specific sectors that could be used by anyone, producing standard performance benchmarks that could be compared to other enterprises focused on that segment. That data is then used as the basis for standard performance benchmarks. Over the past five years, the Lean Data team has gathered social impact data from more than 85,000 customers in 33 countries and worked with more than 150 social enterprises and not-for-profits.