Why is Six Sigma a useful production management methodology in today’s world?

Six Sigma and PPM quality control systems are much tougher than the AQL systems implemented in businesses a decade or so ago. With production increasing for commodity products worldwide and profit margins decreasing, the acceptability of higher percentage production failures can no longer by financially supported. The Six Sigma method also requires reliability to be built in instead of tested in, resulting in the product intrinsically being better. Hope this helps!