Sample Complexity of Multicalibration for Multilevel Properties
- URL: http://arxiv.org/abs/2608.04288v1
- Date: Tue, 04 Aug 2026 23:38:54 GMT
- Title: Sample Complexity of Multicalibration for Multilevel Properties
- Abstract summary: We study multicalibration for a sequence of $k$ properties in which each property is identifiable once the preceding properties are fixed.<n>Even with only polylogarithmically many binary groups, achieving multicalibration error $varepsilon$ requires $widetilde(varepsilon-(k+2))$ samples.
- Score: 52.27687531970317
- License: http://arxiv.org/licenses/nonexclusive-distrib/1.0/
- Abstract: Calibration requires a predictor to be unbiased after conditioning on its own predictions. Multicalibration asks for this guarantee simultaneously across a collection of groups. Many prediction tasks ask for several related features of the same conditional outcome distribution: variance is defined relative to the mean, skewness relative to both mean and variance, and conditional value at risk relative to a quantile. We study multicalibration for a sequence of $k$ properties in which each property is identifiable once the preceding properties are fixed. This framework includes Bayes pairs but does not require the properties to arise from a single loss. For every fixed $k\ge2$, we establish matching upper and lower sample-complexity bounds up to logarithmic factors under regularity conditions. Even with only polylogarithmically many binary groups, achieving multicalibration error $\varepsilon$ requires $\widetildeΩ(\varepsilon^{-(k+2)})$ samples. Conversely, for any finite group family $\mathcal G$, we give a randomized learner using $O(\varepsilon^{-(k+2)}+\varepsilon^{-2}\log|\mathcal G|)$ samples. Thus the sample complexity is $\widetildeÎ(\varepsilon^{-(k+2)})$ for polynomial-size group families. We instantiate the theory for three canonical examples.
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