Six Sigma

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A management strategy that originated in manufaturing but has been spread to other areas of business. The "sigma" referred to can be thought of as the "defect rate" of a process.

Sigma level Defect Rate % Yield
1 69% 31%
2 31% 69%
3 6.7% 93.3%
4 0.62% 99.38%
5 0.023% 99.977%
6 0.00034% 99.99966%
7 0.0000019% 99.9999981%

Studies have shown that the total cost of ownership of data decreases as the defect rate goes down. So a 1.5 sigma improvement in quality can be directly tied to a reduction in the total costs.

Relation to Information Architecture

The goal of Information Architecture is to design solutions that actually deliver benefit in the real world, rather than to aim for some kind of academic perfection. So it is important to realise that some level of "defect" in the information being used is inevitable. There is a cost associated with improving data quality, which must be justified by the benefits improved quality delivers. A Six Sigma based approach can help estimate the amount that an increased quality of data saves the organisation.

If there is only a tiny volume of data then achieving a 100% quality score is quite easy. For any system that is not trivial, especially when it interacts with the real world, the costs of checking increases as the data quality improves. There comes a point at which investing more in data quality cannot be justified by the benefit it delivers.

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The following pages link to here: Data Quality

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