Response to Reviewer gCvg (Part 1)
Dear Reviewer gCvg:
We sincerely thank you for your detailed and constructive feedback. Your insights have helped us conduct more comprehensive experiments and bring valuable new perspectives to the paper. Below, we address your concerns and questions in detail.
**About the discussion of varying model performance and advice on resolution:**
In the Result Section, we have mentioned models that tend to perform well on easy-level questions but show a significant gap in hard-level questions, indicating a lack of domain knowledge, particularly in rule comprehension.
We also found that most proprietary models, along with the Qwen2-VL-72B model, achieved higher G-Eval and human rating scores than the 7B open-source models. This indicates that proprietary models exhibit stronger reasoning abilities than the 7B open-source models. However, none of the MLLMs achieved an average G-Eval score above 3, highlighting a gap in the deep domain knowledge required for reasoning in video-based sports understanding. We have added this finding in the result section.
Regarding the resolution, We have added a Discussion section in Appendix C. We think better frame extraction strategies need to be developed specifically for sports tasks to ensure that the actions critical for reasoning about the question are clearly provided to the model. A more effective grounding method could also enhance the model’s ability to distinguish actions more accurately. During the experiments, we noticed that while models sometimes captured and described most of the correct movements, they often failed to infer the corresponding rule violations. This highlights a significant gap in connecting recognized actions to specific rules, underscoring the need for models to not only identify movements but also to understand what a rule violation should look like.
**About testing prompt strategy in LLM on MLLM:**
We appreciate this suggestion. We have tested additional prompt strategies on MLLMs for SPORTU-video. Specifically, we added two prompt strategies, including X → Y , X → RY. The results show that X → Y achieved the highest overall performance in most of the models, outperforming X → Y R and X → RY. For most models, the accuracy follows the order: X → Y > X → Y R > X → RY. However, as task difficulty increases, especially in hard-level questions that require more reasoning, performance drops significantly for X → RY due to hallucinated rationales, which mislead the model’s answer inference.
For example, Qwen72b achieved 70.95% accuracy in the X → Y setting but dropped to 69.17% in X → Y R and further to 62.51% in X → RY. On hard-level questions, the drop was particularly significant, from 44.12% (X → Y) to 30.55% (X → RY). This highlights the challenges of reasoning-based prompts in complex tasks. This finding has also been introduced in Zhang's work[1]. We have incorporated these insights into Appendix G and H, including additional examples that demonstrate cases where X → Y succeeded while X → RY failed due to hallucinated rationales. The detailed results are presented in the Results section. Additionally, the results are listed in the response of 7Lbr.
**About whether the questions in this dataset can comprehensively detect the models' abilities to understand sports:**
Our dataset is the first benchmark that comprehensively evaluates models' fundamental sports understanding across three distinct difficulty levels. Easy-level questions are designed for individuals with general commonsense and no specific sports knowledge, medium-level questions require foundational sports knowledge beyond commonsense, and hard-level questions target those with an in-depth understanding of specific sports, including sport-specific rule comprehension. This tiered structure provides a comprehensive evaluation of MLLMs' sports comprehension across varying levels of complexity.
**About the low correlation between human and automatic metrics:**
The low Pearson correlation between human evaluations and other metrics highlights the limitations of current evaluation methods for sports-related reasoning tasks. Unlike general domains, sports explanations often rely on precise terminology and detailed action descriptions, where even minor differences can lead to entirely different outcomes. This demonstrates the need for sports-specific evaluation metrics that better capture the nuances of rule-based reasoning. We believe this is an important future direction and a critical step toward developing automatic metrics that align with human judgments.
[1] Z. Zhang et al., “Multimodal chain-of-thought reasoning in language models” TMLR