Federated Imputation under Heterogeneous Feature Spaces

Fuente: arXiv
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Main Authors: Hocine, Imane, Medjadji, Chaimaa, Kubler, Sylvain, Danoy, Gregoire, Traon, Yves Le
Format: Preprint
Published: 2026
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author Hocine, Imane
Medjadji, Chaimaa
Kubler, Sylvain
Danoy, Gregoire
Traon, Yves Le
author_facet Hocine, Imane
Medjadji, Chaimaa
Kubler, Sylvain
Danoy, Gregoire
Traon, Yves Le
contents Federated Learning (FL) enables collaborative training across decentralized clients, but most methods assume aligned feature schemas, an assumption that rarely holds in tabular settings where clients observe only partially overlapping feature subsets. In these heterogeneous feature spaces, parameter-averaging methods (e.g., FedAvg) transfer little information across weakly overlapping or disjoint feature groups, limiting their effectiveness for federated imputation. To overcome this, we propose \textbf{FedHF-Impute}, a federated imputation framework that separates structural feature unavailability from conventional missingness and uses a shared global feature graph to propagate information across statistically related features through message passing. This enables indirect cross-client knowledge transfer, even when features are never jointly observed locally, while preserving standard federated communication. Under simulated partial schema overlap on the SECOM and AirQuality datasets, FedHF-Impute improves imputation accuracy (RMSE) over FL baselines by 26.9\%, and 8.4\% respectively, while achieving comparable performance on PhysioNET, with only a 0.3\% difference relative to the best baseline.
format Preprint
id arxiv_https___arxiv_org_abs_2605_16099
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle Federated Imputation under Heterogeneous Feature Spaces
Hocine, Imane
Medjadji, Chaimaa
Kubler, Sylvain
Danoy, Gregoire
Traon, Yves Le
Machine Learning
Artificial Intelligence
Federated Learning (FL) enables collaborative training across decentralized clients, but most methods assume aligned feature schemas, an assumption that rarely holds in tabular settings where clients observe only partially overlapping feature subsets. In these heterogeneous feature spaces, parameter-averaging methods (e.g., FedAvg) transfer little information across weakly overlapping or disjoint feature groups, limiting their effectiveness for federated imputation. To overcome this, we propose \textbf{FedHF-Impute}, a federated imputation framework that separates structural feature unavailability from conventional missingness and uses a shared global feature graph to propagate information across statistically related features through message passing. This enables indirect cross-client knowledge transfer, even when features are never jointly observed locally, while preserving standard federated communication. Under simulated partial schema overlap on the SECOM and AirQuality datasets, FedHF-Impute improves imputation accuracy (RMSE) over FL baselines by 26.9\%, and 8.4\% respectively, while achieving comparable performance on PhysioNET, with only a 0.3\% difference relative to the best baseline.
title Federated Imputation under Heterogeneous Feature Spaces
topic Machine Learning
Artificial Intelligence
url https://arxiv.org/abs/2605.16099