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Can SGD Select Good Fishermen? Local Convergence under Self-Selection Biases (Extended Abstract)
Proceedings of Thirty Ninth Conference on Learning Theory, PMLR 336:3904-3905, 2026.
Abstract
We revisit the problem of estimating $k$ linear regressors in $d$ dimensions from samples affected by self-selection bias under the maximum selection rule. Our main result is an algorithm with sample complexity $O(d)\cdot \operatorname{poly}(k,1/\varepsilon)$ and running time $\operatorname{poly}(d,k,1/\varepsilon)+(k\log k)^{O(k)}$ for recovering the regressors up to joint squared error $\varepsilon^2$. The key ingredient is the first local-convergence algorithm for the maximum self-selection model. Our approach reduces self-selection to estimation from coarse observations, where the learner observes only the cell of a partition containing the latent sample. The self-selection reduction induces a structured non-convex partition. We prove that this partition preserves enough information locally and that the resulting negative log-likelihood is locally convex around the true parameters. These two geometric properties allow projected stochastic gradient descent, initialized from an existing warm start, to obtain the stated end-to-end guarantee.