Which code is used to indicate why an employee is scheduled on or off?

The correct answer is the one that identifies the specific reason behind an employee's schedule status, whether on duty or on leave. This type of code provides a direct understanding of the attendance management system by clarifying the justification for scheduling decisions.

Earning Codes generally relate to how an employee earns their pay, such as overtime or bonuses, rather than signaling attendance specifics. Time-off Codes are more about the type of leave being taken, but they don’t comprehensively convey the aspect of scheduling either. Staffing Codes can be more operational, categorizing resources for specific shifts or tasks but do not clarify the reasons for an employee's presence or absence.

Thus, the appropriate choice captures the essential information about attendance, making it the most relevant answer.