This all got started when David Lewis declared as something of a thought experiment that all libraries should contribute at least 2.5% of their budgets to create an open scholarly commons. The original idea is in his article “The 2.5% Commitment“. From there, a small group of us thought the idea important enough to explore what it might look like in the real world, including taking on the task of defining what would count as a valid investment in Open, and creating a tool to allow colleges and universities to record over time how their investments in Open have changed.