As said in the short article linked above, DMAIC is to improve an existing process. DMADV is to design a new process. And as suggested, you may find that the existing process is inherently defective and you may be better off to switch to DMADV and redesign. But don’t rush into that. You need factual data that shows that defective outputs from the process are the result of an inherently defective process, not just from less than optimal operations. The scope of a DMADV project is obviously much larger than DMAIC.
There are many methodology and tools differences between DMAIC and DMADV, although there is much in common. But these aren’t things you need to know to answer this particular question. Also, DMADV isn’t the only defined methodology for DFSS (Design For Six Sigma). It’s the most widely accepted.
