What are factors to be considered during size-up?

• A. Environment, nature of incident, field sketch, and resources
• B. Nature of incident, field sketch, occupancy, and report drawn to scale
• C. Facts, probabilities, own situation, decision, and plan of operation
• D. Purpose of size-up, nature of incident, resources, and field sketch

Answer: (C)

Size-up is the mental process of turning what you observe into a clear plan of action. The best answer captures that flow: gather facts, assess what’s likely to happen (probabilities), consider your own situation (resources, safety, constraints), make a decision, and then develop a plan of operation to guide actions. Facts are the reliable scene details you observe. Probabilities help you anticipate likely developments, such as fire behavior or evolving hazards. Your own situation focuses on your crew’s status, available tools, and safety margins. The decision is committing to a course of action, and the plan of operation translates that decision into organized tasks, assignments, and timing to achieve objectives safely and effectively. While other elements like environment, occupancy, or field sketches are useful data or documentation, they don’t represent the essential decision-making loop that drives the incident action plan.