$α$-Variational Inference with Statistical Guarantees
This provides a theoretical foundation for variational inference with convergence guarantees, addressing a key bottleneck in Bayesian computation for practitioners.
The authors introduced α-VB, a family of variational approximations to Bayesian posteriors with provable statistical guarantees, showing that maximizing the evidence lower bound minimizes Bayes risk and that point estimates converge at an optimal rate in various models.
We propose a family of variational approximations to Bayesian posterior distributions, called $α$-VB, with provable statistical guarantees. The standard variational approximation is a special case of $α$-VB with $α=1$. When $α\in(0,1]$, a novel class of variational inequalities are developed for linking the Bayes risk under the variational approximation to the objective function in the variational optimization problem, implying that maximizing the evidence lower bound in variational inference has the effect of minimizing the Bayes risk within the variational density family. Operating in a frequentist setup, the variational inequalities imply that point estimates constructed from the $α$-VB procedure converge at an optimal rate to the true parameter in a wide range of problems. We illustrate our general theory with a number of examples, including the mean-field variational approximation to (low)-high-dimensional Bayesian linear regression with spike and slab priors, mixture of Gaussian models, latent Dirichlet allocation, and (mixture of) Gaussian variational approximation in regular parametric models.