With GPT‑5.5 Instant, we’re seeing a substantial step forward in health, with improvements in recognizing when urgent care may be needed, asking for relevant context, explaining uncertainty, and making complex information easier to understand. On our most challenging health evaluations, GPT‑5.5 Instant now performs at a level comparable to our frontier Thinking models. Because it is available to all free users in ChatGPT, more people can benefit from these improvements.

That progress reflects both advances in model capabilities and the physician-led work behind our health evaluations. Across our efforts, a global network of physicians helps define what “good” looks like in real-world health situations by reviewing example model responses, describing ideal behavior, and identifying failure modes. Working with physicians gives us a way to measure progress in health and improve how ChatGPT responds over time.

In health, progress means delivering responses that are accurate, understandable, and grounded in good judgment: recognizing when more context is needed, explaining uncertainty without overstating confidence, and helping people understand when to seek care.

To measure that progress, we use health-specific evaluations, including HealthBench⁠ and HealthBench Professional⁠(opens in a new window). These evaluations use realistic health conversations and physician-written rubrics to assess qualities like accuracy, safety, communication, context awareness, completeness, and appropriate escalation.