Fine-tuning LLMs: The impact of progressive data

Fine-tuning LLMs: The impact of progressive data

About the session

Why do smaller models perform well on simple training data, yet struggle when that data becomes more sophisticated? In this DevRev Live session, Ahmed Bashir, Ritesh Goru, and Shanay Mehta share lessons from fine-tuning language models for negotiation advice โ€“ a nuanced task where quality cannot be checked with a simple right-or-wrong test.

The discussion follows the team's progression from a dataset generated with Gemini 2.5 Pro to more advanced training data produced using Gemini 3 Pro and Sonnet 4.5. They explore why changing base models and training settings did not close the performance gap, how training loss helps screen experiments, and the trade-offs between larger models, reasoning, and response latency.

Key takeaways

  • Understand how stronger teacher models raise both dataset quality and performance expectations.
  • Learn why rejection sampling and task-specific evaluators matter when preparing training data.
  • Recognize when training loss signals that a smaller model is struggling to learn a more nuanced task.
  • Explore the trade-offs between model size, reasoning, and inference latency.
  • Distinguish improvements from more training data from persistent weaknesses in logic and phrasing.

Agenda

  1. Distillation and initial fine-tuning results

    The initial approach to training smaller models using frontier-model examples.

  2. Stronger teacher models and more nuanced data

    How improved teacher models raised the performance bar.

  3. Comparing base models and training settings

    What the team learned by changing models and training parameters.

  4. Model capacity and training-loss signals

    Using evaluators and training loss to diagnose learning limitations.

  5. Larger models versus reasoning

    The trade-offs between response quality and latency.

  6. Dataset quality, size, and next experiments

    Rejection sampling, data volume, and remaining weaknesses in logic and phrasing.

Speakers

  • Ahmed Bashir

    Ahmed Bashir

    Chief Technology Officer, DevRev

  • RG

    Ritesh Goru

  • Shanay Mehta

    Shanay Mehta

    MTS @ DevRev