ChatGPT is a member of the generative pre-trained transformer (GPT) family of language models. It was fine-tuned (an approach to transfer learning[6]) over an improved version of OpenAI's GPT-3 known as "GPT 3.5".[7] The fine-tuning process leveraged both supervised learning as well as reinforcement learning in a process called reinforcement learning from human feedback (RLHF).   ChatGPT was launched as a prototype on November 30, 2022, and quickly garnered attention for its detailed responses and articulate answers across many domains of knowledge.[3] Its uneven factual accuracy, however, has been identified as a significant drawback.[4] Following the release of ChatGPT, OpenAI's valuation was estimated at US$29 billion in 2023