Which option is NOT a component of the SHELL model?

Which option is NOT a component of the SHELL model?

• A. Procedures
• B. Software
• C. Hardware
• D. Liveware

Answer: (A)

The SHELL model analyzes how people interact with their tools and surroundings to perform tasks safely, focusing on four domains: Software, Hardware, Environment, and Liveware. Software covers the knowledge and instructions that guide action—manuals, checklists, procedures, and software applications. Hardware is the physical equipment and devices involved. Environment includes the physical and organizational setting—lighting, weather, noise, culture, policies. Liveware is the human element—the person or people operating within the system. Procedures aren’t a separate domain; they’re part of Software. They represent the instructional content that tells people what to do and how to do it, not an independent category of the system. That’s why, in the SHELL model, the components are Software, Hardware, Environment, and Liveware, with procedures falling under Software rather than standing alone.

The SHELL model analyzes how people interact with their tools and surroundings to perform tasks safely, focusing on four domains: Software, Hardware, Environment, and Liveware. Software covers the knowledge and instructions that guide action—manuals, checklists, procedures, and software applications. Hardware is the physical equipment and devices involved. Environment includes the physical and organizational setting—lighting, weather, noise, culture, policies. Liveware is the human element—the person or people operating within the system.

Procedures aren’t a separate domain; they’re part of Software. They represent the instructional content that tells people what to do and how to do it, not an independent category of the system. That’s why, in the SHELL model, the components are Software, Hardware, Environment, and Liveware, with procedures falling under Software rather than standing alone.