Chapter 10. Fine-Tuning
Imagine you’ve hired a smart generalist: they communicate clearly, can reason through unfamiliar problems, and learn quickly but they haven’t worked in your domain. They don’t know your jargon or your policies yet. Supervised fine-tuning (SFT) is the process of turning that generalist into a reliable specialist. For LLMs, SFT means taking a pre-trained model and continuing training on a focused dataset so it behaves the way you need for a particular task or product.
Before we get started, we want to clarify that fine-tuning can be supervised or preference-driven. The supervised fine-tuning is SFT, which is the focus of this chapter. In SFT, we train on examples of the form (input, ideal output). We show the model what a good answer looks like, and the model learns to imitate that behavior. Figure 10-1 highlights the SFT stage.
By contrast, preference-driven fine-tuning is often called preference fine-tuning, preference tuning, or simply alignment. This stage is optional and typically comes after SFT. In alignment, instead of providing a single “gold” response, you provide comparisons (or reward signals) that indicate which outputs are better—according to preferences such as helpfulness, harmlessness, or style. The key idea is that once a model is competent (happens during SFT), alignment methods shape which of the many plausible responses it chooses. Methods like RLHF and DPO live here. We will discuss alignment in Chapter 11.
Figure 10-1. Supervised ...
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