What type of feedback is crucial for controlling the outcome of a system?

Measurable evaluations of system performance are essential for controlling the outcome of a system because they provide quantitative data that can be analyzed to assess how well the system is functioning. This feedback allows for continuous monitoring and adjustments to improve efficiency, effectiveness, and overall performance. By analyzing these evaluations, system operators can identify trends, predict issues, and implement corrective actions to steer the system towards desired outcomes.

In contrast, input that initiates the process is important for starting the system but does not provide ongoing information about its operation. Unexpected results from system operations can be informative but are typically symptoms of potential issues rather than structured feedback to help guide the system's ongoing performance. External opinions about the output may provide valuable insights but are subjective and may not accurately reflect the system's performance under quantitative criteria.