Hierarchical Time Series Forecasting with Robust Reconciliation

Fuente: arXiv
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Auteurs principaux: Aikawa, Shuhei, Suzuki, Aru, Yoshitake, Kei, Teshigawara, Kanata, Iwabuchi, Akira, Kobayashi, Ken, Nakata, Kazuhide
Format: Preprint
Publié: 2025
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author Aikawa, Shuhei
Suzuki, Aru
Yoshitake, Kei
Teshigawara, Kanata
Iwabuchi, Akira
Kobayashi, Ken
Nakata, Kazuhide
author_facet Aikawa, Shuhei
Suzuki, Aru
Yoshitake, Kei
Teshigawara, Kanata
Iwabuchi, Akira
Kobayashi, Ken
Nakata, Kazuhide
contents This paper focuses on forecasting hierarchical time-series data, where each higher-level observation equals the sum of its corresponding lower-level time series. In such contexts, the forecast values should be coherent, meaning that the forecast value of each parent series exactly matches the sum of the forecast values of its child series. Existing hierarchical forecasting methods typically generate base forecasts independently for each series and then apply a reconciliation procedure to adjust them so that the resulting forecast values are coherent across the hierarchy. These methods generally derive an optimal reconciliation, using a covariance matrix of the forecast error. In practice, however, the true covariance matrix is unknown and has to be estimated from finite samples in advance. This gap between the true and estimated covariance matrix may degrade forecast performance. To address this issue, we propose a robust optimization framework for hierarchical reconciliation that accounts for uncertainty in the estimated covariance matrix. We first introduce an uncertainty set for the estimated covariance matrix and formulate a reconciliation problem that minimizes the worst-case average of weighted squared residuals over this uncertainty set. We show that our problem can be cast as a semidefinite optimization problem. Numerical experiments demonstrate that the proposed robust reconciliation method achieved better forecast performance than existing hierarchical forecasting methods, which indicates the effectiveness of integrating uncertainty into the reconciliation process.
format Preprint
id arxiv_https___arxiv_org_abs_2510_20383
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Hierarchical Time Series Forecasting with Robust Reconciliation
Aikawa, Shuhei
Suzuki, Aru
Yoshitake, Kei
Teshigawara, Kanata
Iwabuchi, Akira
Kobayashi, Ken
Nakata, Kazuhide
Machine Learning
This paper focuses on forecasting hierarchical time-series data, where each higher-level observation equals the sum of its corresponding lower-level time series. In such contexts, the forecast values should be coherent, meaning that the forecast value of each parent series exactly matches the sum of the forecast values of its child series. Existing hierarchical forecasting methods typically generate base forecasts independently for each series and then apply a reconciliation procedure to adjust them so that the resulting forecast values are coherent across the hierarchy. These methods generally derive an optimal reconciliation, using a covariance matrix of the forecast error. In practice, however, the true covariance matrix is unknown and has to be estimated from finite samples in advance. This gap between the true and estimated covariance matrix may degrade forecast performance. To address this issue, we propose a robust optimization framework for hierarchical reconciliation that accounts for uncertainty in the estimated covariance matrix. We first introduce an uncertainty set for the estimated covariance matrix and formulate a reconciliation problem that minimizes the worst-case average of weighted squared residuals over this uncertainty set. We show that our problem can be cast as a semidefinite optimization problem. Numerical experiments demonstrate that the proposed robust reconciliation method achieved better forecast performance than existing hierarchical forecasting methods, which indicates the effectiveness of integrating uncertainty into the reconciliation process.
title Hierarchical Time Series Forecasting with Robust Reconciliation
topic Machine Learning
url https://arxiv.org/abs/2510.20383