How is Six Sigma different from other Traditional Approaches.

Six Sigma differs from traditional performance improvement programs in its focus on input variables. While traditional methods depend on measuring outputs and establishing control plans to shield customers from organizational defects, a Six Sigma program demands that problems be addressed at the root level, eliminating the need for unnecessary inspection and rework processes.
Also, while other programs mention philosophies, ideas, and requirements (e.g. ISO 9001 specifies requirements) Six Sigma provides a structured Roadmap on how to bring out the benefits.