s1: Simple test-time scaling

Muennighoff et al., 2025, s1 (Proceedings of the 2025 Conference on Empirical Methods in Natural Language Processing)

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2.2 Final selection of 1K samples

  1. How did s1 filter 59K questions down to s1K?
    Quality: drop API errors and badly formatted samples. Difficulty: drop questions that Qwen2.5-7B-Instruct or Qwen2.5-32B-Instruct already solves. Diversity: repeatedly pick a domain (from the Mathematics Subject Classification) uniformly at random, then a question from it, favoring longer reasoning traces, until there are 1,000 across 50 domains.
    • Muennighoff et al., 2025, s1 (Proceedings of the 2025 Conference on Empirical Methods in Natural Language Processing), §2.2, p. 20277
  2. About half of the s1K answers are wrong. Why did it still work?
    The model is fine-tuned to imitate the reasoning process, not to memorize answers: SFT here mainly teaches reasoning patterns, so traces with wrong final answers still help.
    • Muennighoff et al., 2025, s1 (Proceedings of the 2025 Conference on Empirical Methods in Natural Language Processing), §2.2, p. 20277

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