A deterministic model is a system where the same input always produces the same output—no randomness, no surprises. In contrast to probabilistic models like ChatGPT, deterministic models are rule-based and highly predictable. This glossary entry explains where deterministic models are used, especially in structured HR tasks like rule-based decision-making or workflows. If you’re exploring AI systems and want to understand the difference between logic-driven and data-driven tools, start here.