Efficient nonparametric statistical inference on population feature importance using Shapley values

Fuente: arXiv
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Main Authors: Williamson, Brian D., Feng, Jean
Format: Preprint
Published: 2020
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author Williamson, Brian D.
Feng, Jean
author_facet Williamson, Brian D.
Feng, Jean
contents The true population-level importance of a variable in a prediction task provides useful knowledge about the underlying data-generating mechanism and can help in deciding which measurements to collect in subsequent experiments. Valid statistical inference on this importance is a key component in understanding the population of interest. We present a computationally efficient procedure for estimating and obtaining valid statistical inference on the Shapley Population Variable Importance Measure (SPVIM). Although the computational complexity of the true SPVIM scales exponentially with the number of variables, we propose an estimator based on randomly sampling only $Θ(n)$ feature subsets given $n$ observations. We prove that our estimator converges at an asymptotically optimal rate. Moreover, by deriving the asymptotic distribution of our estimator, we construct valid confidence intervals and hypothesis tests. Our procedure has good finite-sample performance in simulations, and for an in-hospital mortality prediction task produces similar variable importance estimates when different machine learning algorithms are applied.
format Preprint
id arxiv_https___arxiv_org_abs_2006_09481
institution arXiv
publishDate 2020
record_format arxiv
spellingShingle Efficient nonparametric statistical inference on population feature importance using Shapley values
Williamson, Brian D.
Feng, Jean
Methodology
Machine Learning
The true population-level importance of a variable in a prediction task provides useful knowledge about the underlying data-generating mechanism and can help in deciding which measurements to collect in subsequent experiments. Valid statistical inference on this importance is a key component in understanding the population of interest. We present a computationally efficient procedure for estimating and obtaining valid statistical inference on the Shapley Population Variable Importance Measure (SPVIM). Although the computational complexity of the true SPVIM scales exponentially with the number of variables, we propose an estimator based on randomly sampling only $Θ(n)$ feature subsets given $n$ observations. We prove that our estimator converges at an asymptotically optimal rate. Moreover, by deriving the asymptotic distribution of our estimator, we construct valid confidence intervals and hypothesis tests. Our procedure has good finite-sample performance in simulations, and for an in-hospital mortality prediction task produces similar variable importance estimates when different machine learning algorithms are applied.
title Efficient nonparametric statistical inference on population feature importance using Shapley values
topic Methodology
Machine Learning
url https://arxiv.org/abs/2006.09481