What is the essential difference(s) between quality control and quality assurance?

The essential difference between quality control and quality assurance lies in their focus and approach to maintaining standards. Quality control is primarily concerned with identifying and correcting defects in the products or processes after they have occurred. It involves testing and inspection to find mistakes that may have already been made. Quality assurance, on the other hand, emphasizes the systematic processes and practices that are put in place to prevent mistakes from occurring in the first place. It seeks to improve processes and ensure that the end products meet certain quality standards before any issues arise.

By understanding that quality control is about finding and rectifying errors, while quality assurance is focused on prevention and system improvement, the answer that encompasses both these perspectives highlights the comprehensive nature of these concepts. Thus, stating that one has a feedback loop (which is indicative of both processes) and the other focuses on mistake prevention provides a clear illustration of their roles in a quality management system, making the combined answer the most comprehensive and accurate portrayal of their essential differences.