What’s been the impact of Retro Funding so far?

This post examines the before-and-after impact of Optimism's Retro Funding (RF) on open source software projects, and reports that developer activity rose across cohorts after RF3 while cautioning that the data cannot establish causation. Among the 315 projects that participated in RF3, average full-time active developers grew from around 225 to over 300, a 13.9% growth rate over the past year. Projects that had been in RF1 or RF2 as well as RF3 grew faster than the RF3-only group, while a baseline of 852 projects that never received RF showed a -0.4% change over the same period.