The big difference between business process reengineering and continuous improvement programs like TQM or Six Sigma is that

business process reengineering is a tool for achieving one$-$time quantum improvement whereas TQM and Six Sigma programs aim at ongoing incremental improvements.

reengineering helps create core competencies whereas TQM$/$Six Sigma are tools for making a core competence stronger and more cost efficient.

reengineering is a tool for revamping entire company value chains whereas TQM$/$Six Sigma concern instituting defect$-$free production methods and delivering world$-$class customer service.

reengineering aims at remodeling and updating particular value chain activities to achieve dramatic gains in product quality whereas TQM and Six Sigma are best used for achieving small, but ongoing, reductions in operating costs.

business process reengineering aims at creating altogether new best practices whereas TQM and Six Sigma are used to make gradual improvements in existing best practices.