Open-source software has become the backbone of modern scientific computing, including Bayesian statistics. NumFOCUS provides the organizational, legal, and financial infrastructure that sustains many of the most important open-source projects in data science and scientific computing, ensuring their long-term viability and continued development.
Mission and Structure
Founded in 2012, NumFOCUS is a 501(c)(3) nonprofit organization based in the United States. Its mission is to promote open practices in research, data, and scientific computing by supporting the development of open-source tools and the communities that build them. NumFOCUS achieves this through fiscal sponsorship, grants, educational programs, and community events.
As a fiscal sponsor, NumFOCUS provides a legal and financial home for open-source projects. This means that projects like Stan, PyMC, and ArviZ can receive tax-deductible donations, apply for grants, and manage funds without needing to incorporate separately. This infrastructure is crucial for the sustainability of volunteer-driven open-source projects.
Bayesian Projects Under NumFOCUS
Several of the most important tools in Bayesian statistics are sponsored or affiliated projects of NumFOCUS:
Stan is a sponsored project, receiving organizational support and funding for its development as the leading probabilistic programming platform using Hamiltonian Monte Carlo. PyMC is likewise a sponsored project, supported in its mission to bring Bayesian modeling to the Python ecosystem. ArviZ, the Bayesian diagnostics and visualization library, is a NumFOCUS-affiliated project. Beyond the specifically Bayesian tools, NumFOCUS also supports foundational libraries such as NumPy, pandas, Matplotlib, and Jupyter, which form the computational substrate on which Bayesian analysis in Python depends.
Programs and Activities
NumFOCUS runs several programs that benefit the open-source scientific computing community. The Small Development Grants program provides funding for targeted improvements to sponsored projects. PyData, a NumFOCUS educational program, organizes conferences and meetups around the world where Bayesian methods are frequently featured. The organization also participates in Google Summer of Code, mentoring students who contribute to sponsored projects.
NumFOCUS is founded to promote sustainable open-source scientific computing.
PyMC becomes a NumFOCUS sponsored project.
Stan becomes a NumFOCUS sponsored project, securing organizational support for its continued development.
"Open-source software is the lifeblood of modern data science. NumFOCUS ensures that the projects we all depend on have the support they need to thrive."— NumFOCUS mission statement
Impact on Bayesian Statistics
The support provided by NumFOCUS has been instrumental in the growth and stability of Bayesian software. By providing financial infrastructure, governance support, and community-building events, NumFOCUS has helped ensure that powerful Bayesian tools remain freely available, well-maintained, and accessible to researchers and practitioners worldwide. The organization's role illustrates the critical importance of institutional support for the open-source tools that increasingly define modern statistical practice.