Test-Time Adaptation (TTA) has recently emerged as a promising approach for tackling the robustness challenge under distribution shifts. However, the lack of consistent settings and systematic studies in prior literature hinders thorough assessments of existing methods. To address this issue, we present TTAB, a test-time adaptation benchmark that encompasses ten state-of-the-art algorithms, a diverse array of distribution shifts, and two evaluation protocols. Through extensive experiments, our benchmark reveals three common pitfalls in prior efforts. First, selecting appropriate hyper-parameters, especially for model selection, is exceedingly difficult due to online batch dependency. Second, the effectiveness of TTA varies greatly depending on the quality and properties of the model being adapted. Third, even under optimal algorithmic conditions, none of the existing methods are capable of addressing all common types of distribution shifts. Our findings underscore the need for future research in the field to conduct rigorous evaluations on a broader set of models and shifts, and to re-examine the assumptions behind the empirical success of TTA. Our code is available at \url{https://github.com/lins-lab/ttab}.

本文提出了针对测试时间适应（TTA）的测试基准TTAB，通过实验表明：在线批次依赖性使得选择适当的超参数尤其是选择模型极为困难，TTA的有效性取决于模型的质量和属性，并且即使在最优算法条件下，现有方法也无法处理所有常见类型的分布转移，因此需要在更广泛的模型和转移集上进行严格评估和重新审视TTA的实证成功条件。

关于测试时适应性的陷阱