How do SFT, DPO, and RLHF differ as alignment methods?
PICTURE THIS: SUPERVISED LEARNING
Simple meaning
SFT clones demonstration answers via supervised loss.
WHY — Tokens instead of words?
LLMs use tokens (not full words) because it helps them:
question about Fine-tuning vs RAG.
trade-offs, and what you would actually do on a GenAI / LLM project - not buzzwords.
Each piece maps to a number the network can learn.
Fixed pieces are what transformers expect as input.
STEPS — What happens step by step?
Before you speak the answer, walk the interviewer through these steps:
- 1SFT clones demonstration answers
via supervised loss.
- 2DPO trains on preferred
versus rejected pairs without a separate reward model.
- 3Classic RLHF fits a
reward model then PPO-updates the policy, which is more complex and can chase reward hacks.
- 4Give an example
One tiny concrete case you can say aloud.
- 5Common mistake
What juniors usually get wrong.
- 6Close
When you pick this over the alternative.
EXAMPLE — See it in action
Here's a short line you can speak, broken into clear beats:
Note: Adapt this scaffold to your own project — keep it under 60–90 seconds.
Key takeaway
SFT clones demonstration answers via supervised loss. DPO trains on preferred versus rejected pairs without a separate reward model.