SOA is a “thinking process” rather than an architecture tool or a method framework.
Six Sigma is a measure of quality that strives for perfection. It is attributed as a disciplined, data-driven approach and methodology for eliminating defects. It is also a way to enable the evaluation,re-evaluate of an organization,project’s financial benefits, and to verify them.
This article “SOA with Six Sigma Methodology: A Process for E-business Development” lays out how the Principles of Six Sigma methodology combine with philosophy of SOA to frame a process for E-business Development.