Defects. Production of defective parts or firefighting to correct the defects. Rework, scrap, replacement, and inspection mean wasteful handling, time, and effort. 
Defects in software development costs heavily to the vendors and customers alike. Detecting the defects early by using Agile approaches likes TDD, Pair programming, Extreme programming, having defect prevention plan in place are critical for producing high quality software. Finding and fixing a software problem after delivery is often many times more expensive than finding and fixing it during the requirements and design phase.
Agile helps to minimize the defect age of software by typically reducing the presence of defects age by (maximum) a day or two. As customer and all stakeholders are continuously collaborated in making decisions Agile suits best for faster and better quality software development.
Better to prevent defects by identifying causes and systematically eliminating is the key to sustainable software development. Having solid reviews also benefits the projects in defect reduction. Using automated test suits and code integration tools are best solutions in preventing defects.
Peer reviews catch 60 % of the defects. Objective based reviews catch 35% more defects than non-directed reviews. Toyota puts it beautifully about removal of MUDAs as WAR on WASTE.
Filed under: Lean
