Metrics-driven improvement leads to changes guided by the data surrounding the problem and informed solutions, not by opinions and conjecture. Importantly, metrics-driven outcomes are repeatable and scalable.
Agile metrics
Built-in Quality is a critical principle of agile teams that ensures the quality of their product. A robust Definition of Done is key as is a common understanding of what it means to turn items from the Product Backlog into something that is of high enough quality that it can be handed over or used by customers.