What is InstructGPT and Key Differences from ChatGPT

Massar Tanya Ming Yau Chong  Jan 10, 2024 10:09  UTC 02:09

2 Min Read

InstructGPT is a refined iteration of OpenAI's GPT-3 model, expertly fine-tuned to better comprehend and execute user commands, while producing outputs that are more ethical, accurate, and in harmony with human intentions. This advancement signifies a substantial stride in the evolution of AI models, steering them towards more responsive and ethically attuned interactions. InstructGPT is based on the research paper titled "Training Language Models to Follow Instructions" and its official page on OpenAI is here.

Although both InstructGPT and ChatGPT are developed by OpenAI and these two models are grounded in the GPT (Generative Pre-trained Transformer) architecture , they are different in methodologies, objectives and training approaches.

Conceptual Framework

ChatGPT: Primarily designed as a conversational agent, ChatGPT excels in generating human-like text responses. It's fine-tuned on a blend of supervised and reinforcement learning techniques with an emphasis on conversational tasks.

InstructGPT: While also based on the GPT architecture, InstructGPT is specifically fine-tuned to follow instructions more effectively. It marks a shift towards aligning the model's responses with user intent, emphasizing the accuracy and relevance of its outputs.

Training Methodology

ChatGPT: Utilizes a combination of reinforcement learning from human feedback (RLHF), supervised fine-tuning, and a continual learning process that involves interaction with users and subsequent updates.

InstructGPT: Incorporates a novel training regime that includes collecting human-written demonstrations and preferences. It employs supervised fine-tuning (SFT) followed by further refinement using reinforcement learning from human feedback (RLHF), emphasizing alignment with human instructions and intents.

Functional Objectives

ChatGPT: Aims to generate coherent, contextually appropriate, and engaging dialogue, addressing a wide range of conversational topics while maintaining a natural flow of interaction.

InstructGPT: Focuses on accurately interpreting and executing a variety of instructions, striving to produce outputs that are not only contextually relevant but also adhere closely to the specific guidance provided by the user.

Performance and Capabilities

ChatGPT: Demonstrates robust conversational abilities, capable of maintaining long and complex dialogues across diverse domains, but may not always align closely with specific user instructions.

InstructGPT: Exhibits a marked improvement in following specific instructions, delivering outputs that are more aligned with user requests, even on tasks that are less conversational and more directive in nature.

Evaluation and Metrics

ChatGPT: Evaluated primarily on its ability to maintain engaging and contextually relevant conversations, with metrics often centered around dialogue coherence, fluency, and user engagement.

InstructGPT: Assessed based on its adherence to and execution of user instructions, with a strong emphasis on the accuracy, relevance, and helpfulness of its responses in relation to the specific tasks given.


In summary, while both models share a common foundation in the GPT architecture, InstructGPT represents a focused evolution towards better understanding and executing user instructions, setting it apart from the more conversationally inclined ChatGPT. This shift underscores OpenAI's commitment to enhancing the practical utility and user experience of language models in real-world applications.

Image source: Shutterstock

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