Unsupervised Domain Adaptation for Binary Classification with an Unobservable Source Subpopulation

TMLR Paper7026 Authors

15 Jan 2026 (modified: 16 Jan 2026)Under review for TMLREveryoneRevisionsBibTeXCC BY 4.0
Abstract: We study an unsupervised domain adaptation problem where the source domain consists of subpopulations defined by the binary label $Y$ and a binary background (or environment) $A$. We focus on a challenging setting in which one such subpopulation in the source domain is unobservable. Naively ignoring this unobserved group can result in biased estimates and degraded predictive performance. Despite this structured missingness, we show that the prediction in the target domain can still be recovered. Specifically, we rigorously derive both background-specific and overall prediction models for the target domain. For practical implementation, we propose the distribution matching method to estimate the subpopulation proportions. We provide theoretical guarantees for the asymptotic behavior of our estimator, and establish an upper bound on the prediction error. Experiments on both synthetic and real-world datasets show that our method outperforms the naive benchmark that does not account for this unobservable source subpopulation.
Submission Type: Long submission (more than 12 pages of main content)
Previous TMLR Submission Url: https://openreview.net/forum?id=9XmNbzTBXn&referrer=%5BAuthor%20Console%5D(%2Fgroup%3Fid%3DTMLR%2FAuthors%23your-submissions)
Changes Since Last Submission: We are so sorry and feel bad that our last submission was formatted incorrectly. In this version, we corrected it and double checked everything to make sure that there are no other errors. Thank you for the consideration.
Assigned Action Editor: ~Sanghyuk_Chun1
Submission Number: 7026
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