Philip Crosby's Zero Defects & 6 Sigma
Philip Crosby, the Guru of Quality Management, was a legend in the discipline of quality. A noted quality professional, consultant, and author, he is widely recognized for promoting the concept of "zero defects" and for defining quality as conformance to requirements.
Zero defects is a performance standard and method states that if people commit themselves to watching details and avoiding errors, they can move closer to the goal of zero defects.
Zero defects is a way of thinking and doing that reinforces the compliance management notion that defects are not acceptable, and that everyone should "do things right the first time". The idea here is that you can increase profits both by eliminating the cost of failure and increasing revenues through increased customer satisfaction. Zero defects is NOT about being perfect, it's about changing your perspective, and it does this by demanding that you:

• Recognize the high cost of quality issues.

• Continuously think of the places where flaws may be introduced.

• Work proactively to address the flaws in your systems and processes, which allow defects to occur.

"Zero defects" is not a program, nor does it have distinct steps to follow or rules to abide by: which is perhaps why zero defects can be so effective, as it's adaptable to any situation, business, profession or industry.4

"Zero Defects" is a goal and "6 sigma" is how to achieve the goal