Which of these defines 'feedback' in a system?

Feedback in a system refers to the information that assesses the effectiveness of the process, informing stakeholders about the outcomes of their actions or decisions. It acts as a performance indicator that provides insights into whether the system is functioning as intended and helps identify necessary adjustments to improve performance or correct issues. This concept is vital in various fields, such as engineering, technology, and business, where continuous improvement is essential.

The other choices represent different concepts that do not specifically pertain to the definition of feedback. For instance, measuring the target market focuses on identifying and analyzing potential customers, while promotional material involves strategies to communicate the product's value to consumers. A summary of lessons learned refers to the reflection on past experiences and insights gained, which may inform future actions but does not directly describe the role of feedback in assessing a system’s performance.