Reinforcement Learning from Human Feedback (RLHF) is a machine learning training method where human reviewers guide how an AI model learns by rating, ranking, or correcting its outputs. In reinforcement learning from human feedback, the system does not rely only on automated scores. Instead, human feedback is used as the reward signal that tells the model which responses match human preferences and which ones should be avoided. RLHF is widely used when training large language models, generative AI systems, and conversational AI where output quality depends on human judgment, not just statistical accuracy.
Reinforcement learning from human feedback combines reinforcement learning with supervised feedback collected from people. In reinforcement learning, a model improves by receiving rewards or penalties based on its actions. In RLHF, those rewards come from human reviewers. Annotators compare model outputs, rank them, or rewrite them, and that feedback is used to train a reward model that represents human preferences. The main model is then fine-tuned using reinforcement learning so that future responses are closer to what reviewers selected.
RLHF is usually applied after a base model has already been trained on large volumes of training data. A model trained only on raw training data can produce fluent text, but the responses may be incorrect, unsafe, or not aligned with user intent. Reinforcement learning from human feedback is used as a fine-tuning step to correct this. Human annotators review model outputs and provide preference rankings, corrections, or quality scores. These review steps are often part of structured data labeling workflows such as response ranking, evaluation, and text annotation [Text annotation].
A typical RLHF pipeline follows a repeatable loop:
For example, when training a chatbot, the system may generate several answers to the same question. Human annotators compare the responses and choose the one that best matches human expectations. Responses that are incorrect, unsafe, or irrelevant are ranked lower. The reward model learns from these rankings, and reinforcement learning adjusts the model so that similar prompts produce better outputs in the future. This process is also used in search relevance tuning, generative AI evaluation, and content moderation models where automated rules cannot fully measure quality.
RLHF is important for AI alignment, which means making sure model behavior matches human intent and acceptable use. A response can be grammatically correct but still misleading or harmful. Human feedback adds context that cannot be learned from training data alone. Because of this, reinforcement learning from human feedback is commonly used in human-in-the-loop (HITL) pipelines where reviewers continuously check predictions and provide corrections. Large-scale AI projects combine RLHF with data labeling, quality review, and evaluation workflows managed through annotation platforms and trained review teams.
As AI systems become more complex, reinforcement learning from human feedback has become a standard fine-tuning method for improving reliability, safety, and usefulness. Models trained with RLHF are more likely to produce outputs that follow human preferences, respect guidelines, and behave consistently in real-world applications