Which of the following is NOT a factor that drives span of control?

The correct answer is the size of the incident. Span of control refers to the number of subordinates that a supervisor can manage effectively at a given time. Factors such as the number of resources involved, the severity of the incident, and the duration of the incident directly affect how many personnel and resources a supervisor can oversee.

The number of resources influences span of control as more resources often require more management oversight to ensure effectiveness and safety. Similarly, severity impacts span of control since more severe incidents may demand heightened attention to detail and quick decision-making, necessitating a smaller span to maintain effective supervision. The duration of the incident also matters; as the incident unfolds over a longer period, it may require adjustments to the supervision structure, potentially affecting how many people a supervisor can manage effectively.

These factors highlight the complexity and dynamic nature of emergency situations, while the sheer size of the incident, though important in some contexts, does not inherently dictate how many individuals a supervisor can control. This differentiation underscores the relevance of the other options in determining the optimal span of control in incident management.