Benchmarking Transferability: A Framework for Fair and Robust Evaluation
Alireza Kazemi, Helia Rezvani, Mahsa Baktashmotlagh
TL;DR
The paper addresses the instability and limited generalizability of existing transferability estimation methods in cross-domain transfer learning. It introduces TransferTest, a benchmarking framework that supports label-free evaluation and source-dataset independence, and proposes a weight-based transferability metric using the 1-Wasserstein distance between pre- and post-tuning weight distributions. By evaluating across diverse source datasets, model complexities, and fine-tuning strategies, the authors show that their Wasserstein-based approach yields more robust rankings (measured by Kendall's tau) and achieves a 3.5% improvement in head-training scenarios. This framework and metric offer a practical, reliable tool for model selection in real-world cross-domain applications while highlighting the limitations of traditional, label-dependent transferability estimators.
Abstract
Transferability scores aim to quantify how well a model trained on one domain generalizes to a target domain. Despite numerous methods proposed for measuring transferability, their reliability and practical usefulness remain inconclusive, often due to differing experimental setups, datasets, and assumptions. In this paper, we introduce a comprehensive benchmarking framework designed to systematically evaluate transferability scores across diverse settings. Through extensive experiments, we observe variations in how different metrics perform under various scenarios, suggesting that current evaluation practices may not fully capture each method's strengths and limitations. Our findings underscore the value of standardized assessment protocols, paving the way for more reliable transferability measures and better-informed model selection in cross-domain applications. Additionally, we achieved a 3.5\% improvement using our proposed metric for the head-training fine-tuning experimental setup. Our code is available in this repository: https://github.com/alizkzm/pert_robust_platform.
