Often I get confused between DPMO (Defects per Million Opportunities) and DPPM (Defective Parts Per Million) ...

can you pls clarify and explain when to use what...

The difference lies in the definition iteself.

DPMO (Defects per Million Opportunities) talk about the defects while

DPPM (Defectives parts per Million) talks about the defectives.

Take an example:

A car manufacturer produces 1000 cars with each car having 50 checkpoints. Hence

Units - 1000

Opportunities - 1000*50 = 50000

Assume, 10 cars are defective while the total number of defects are 250 (i.e. these 10 cars cumulatively failed on 250 checkppoints). Hence

Defectives - 10

Defects - 250

DPMO = 250/50000*1000000 = 5000

DPPM = 10/1000*1000000 = 10000

Typically in a service industry, Customer is more concerned with DPPM. For a service provider it makes more sense to look at DPMO. Even if they start working with DPPM, they will eventually have to drill down to the defects that are rendering the service as defective.

Not sure if the same logic applies to manufacturing, but even though DPPM is an excellent metric to track the performance of the manufacturing unit, for any improvements you still need to look at DPMO.

Hi Mayank, 

 

The story in manufacturing is also same. Automotive clients are more concerned about ppm (parts per million defective) while process owners focus at Defects so as to ensure no Defectives.  

For  Product Audits Defects per Vehicle ( DPU ) is the target

For Supplier Parts PPM is the target

Thanks Mayank. The example that you used explained the difference clearly.

 

So, if focus is on defects, then the question of defectives would not arise. And this would lead to no defectives.