A new strategy for finite-sample valid prediction of future insurance claims in the regression setting
Liang Hong
TL;DR
This work addresses the lack of finite-sample valid prediction intervals for future insurance claims in the regression setting by proposing a general strategy that converts an unsupervised iid predictive method into regression predictions. The core idea writes $Y = h(X) + W$ with $W = Y - h(X)$, constructs a finite-sample valid interval for $W_{n+1}$ using conformal/prediction techniques, and translates it back to a $Y$-interval via $L(W^n) + h(X_{n+1})$ and $U(W^n) + h(X_{n+1})$, yielding infinite families of finite-sample valid intervals for $Y_{n+1}$. The approach, demonstrated through simulations and automobile-claims data, achieves nominal coverage with efficiency that depends on the chosen transformation $h$, offering actuaries a model-free, information-rich mechanism for interval prediction that leverages predictors while preserving finite-sample guarantees. It extends the applicability of conformal prediction into regression for insurance contexts and provides practical guidance on selecting transformations to balance interval length and coverage. $Y = f^*(X) + \varepsilon$ with $W = Y - h(X)$ underpins the theoretical framing, and the method remains broadly applicable beyond insurance to any regression setting requiring finite-sample predictive intervals.
Abstract
The extant insurance literature demonstrates a paucity of finite-sample valid prediction intervals of future insurance claims in the regression setting. To address this challenge, this article proposes a new strategy that converts a predictive method in the unsupervised iid (independent identically distributed) setting to a predictive method in the regression setting. In particular, it enables an actuary to obtain infinitely many finite-sample valid prediction intervals in the regression setting.
