Explanation Stability of Test-Time Adaptation in Computational Pathology: A Large-Scale Benchmark
This study addresses the underexplored trade-off between accuracy and explanation stability in test-time adaptation (TTA) for computational pathology. While TTA can enhance model accuracy, it may compromise the stability of model explanations, thereby undermining clinical trustworthiness. The authors present the first large-scale systematic evaluation of 17 TTA methods across the Camelyon17 and NCT-CRC-HE datasets, examining their impact on explanation stability using four attribution techniques and encompassing convolutional networks, Vision Transformers, and foundation models in pathology—totaling 2,958 experiments. Their findings reveal that explanation stability is decoupled from predictive accuracy and should be treated as an independent reliability metric for TTA. Notably, TTA strategies that freeze the backbone yield the most stable explanations, whereas continual adaptation approaches like CoTTA induce significant explanation drift. Convolutional architectures exhibit greater sensitivity to TTA-induced instability than Transformers. The complete benchmark and evaluation protocol are publicly released.