Defects Per Million Opportunities and How to Calculate Them

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There are many reasons why organizations should empower their staff with a Six Sigma Green Belt certification. One of them is that they learn useful metrics like defects per million units (DPMO). This metric is one of the most critical components in helping Six Sigma Green Belts (and above) drive process improvement and decrease variation.

Even if a worker is not a Belt, they still stand to gain by understanding what DPMO is and how it can be calculated.

What are Defects?

A defect is any imperfection that makes a product less valuable. It is important to note that the presence of a default does not necessarily make a product defective. It would take a significant defect or number of defects to render a product defective (this is another way of saying that the product is broken and can’t be sold).

What are Opportunities?

Opportunities are the total number of possible defects per production run. This means that if each product we produce has five defect opportunities per unit and we produce 100 units of that product, the total number of defect opportunities is 500. 

How to Calculate DPMO

To calculate DPMO, you must take the number of units and multiply them by the number of defect opportunities per unit. Then you take that number and divide it by the total number of defect opportunities. Finally, you multiply that number by one million to get DPMO.

This can best be illustrated by the formula below:

DPMO = (total defect opportunities / (# of units * defect opportunities per unit)) * one million

To achieve Six Sigma, you need to have 3.4 defects per million opportunities. DPMO has a simple formula, but the results of measuring it can be profound. And it needs to be measured more than once due to Six Sigma’s emphasis on continuous improvement.

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