When machine learning systems face new data, they can fail in subtle ways: the inputs may change, the labels may change, or both may shift at once. This paper tackles that general problem of distribution shift, which is one of the main reasons models break after deployment. The authors point out that existing theory often assumes overly neat cases and can’t actually be estimated from samples. Their key idea is to use entropic optimal transport to define a more flexible notion of concept shift, which they call gamma-star concept shift, even when source and target data don’t overlap neatly. From there, they derive a unified error bound covering both covariate shift and concept shift, and they also build estimators with concentration guarantees. The result is DataShifts, a practical tool for quantifying how much a dataset has changed and how that change affects model error. That matters because it turns abstract shift theory into something practitioners can measure and use.
Also spotted that day
Previous daily papers