dpo

Alignment has become a baseline expectation even beyond 'safety' roles. The interviewer is looking for the three-stage RLHF pipeline and a sharp account of why DPO threw out the reward model completely. Here is the answer that leads with mechanism, not the buzzwords.

DPO simplified RLHF, and a family of variants now trade off what data and reference model they require. The signal is knowing what each variant drops or alters (reference model, paired data, separate SFT stage). Here is the answer.

DPO is simple and stable, but it can drive down the probability of chosen responses, overfit the preference margin, and magnify length bias. The signal is naming these and the variants that fix each.