Human factors, also known as ergonomics, is a scientific discipline that applies psychological and physiological principles to the engineering and design of products, processes, and systems. It is concerned with understanding and managing the capabilities and limitations of people to optimize human performance, health, safety, and habitability. Human factors interventions aim to ensure a good "fit" between people, the equipment they use, the task they carry out, and the environment in which they work.

The term "human factors" is an umbrella term for several areas of research that include human performance, technology design, and human-computer interaction. It is a profession that focuses on how people interact with products, tools, procedures, and any processes likely to be used by people. Human factors interventions will not be effective if they consider these aspects in isolation. The scope of what we mean by human factors includes organizational systems and is considerably broader than traditional views of human factors/ergonomics.

Human factors is concerned with what people are being asked to do (the task and its characteristics), who is doing it (the individual and their competence), and where they are working (the organization and its attributes), all of which are influenced by the wider societal concern, both local and national. The field approaches design with the "user" as its focal point.

In summary, human factors is a scientific discipline that applies systematic methods and knowledge about people to evaluate and improve the interaction between individuals and products, processes, and systems. It is concerned with optimizing human performance, health, safety, and habitability by understanding and managing the capabilities and limitations of people.