DFSS: Design For Six Sigma, also known as DMADV. This is a variant of the traditional DMAIC Six Sigma methodology.

DFSS is used when a new process has to be implemented, as opposed to the traditional method which is used for existing processes. Once the process is active, DMAIC will come into play.

This also begins by asking you to define what you want to achieve with your new process. e.g. If you decide to build a new word-processing software, what are the exact features you want to achieve? In DFSS, it is critical that your process is so designed as to meet customer aspirations, because the prime goal of Six Sigma is to maximise customer satisfaction.

Then you must measure how ready you are to implement the process. What are the risks involved, what is your production capacity, have you got the right manpower etc. The operative term here is ‘Critical To Quality’ (CTQ) – every aspect that has a role in determining how the final output will be must be taken care of, you must have reliable data on these.

Again, like in DMAIC, you analyze and determine the best path to the end-point. This is achieved by the design of your process – what are parameters you will consider from the available data, how much error can you tolerate (every design will have its inherent defects that may not be apparent when you start out).

Once ready, begin to actually design the process. You must keep asking yourself and your team – how efficient can you make it, do you have an alternate design, how can you test alternate designs. Attention to detail is the difference maker.

The end of the design is only the beginning of the regular use of the process to achieve the new goals. Before that you must verify the design, to ensure that the process is able to consistently achieve the desired results, with no more than 3.4 DPMO. This involves doing multiple pilot runs before scaling it up to the required volumes.

Lean Six Sigma: While the DMAIC and DFSS Six Sigma processes focus on increasing efficiency and eliminating defects form the process, Lean Six Sigma has the additional goal of reducing wastage in the process. It comes from applying Six Sigma along with Lean Manufacturing.

‘Waste’ here is defined as the expenditure of resources for any goal other than the creation of ‘value’ for the end customer. ‘Value’ is simply something the customer will pay for. E.g. while employee perks may add to the price of the product or service, the customer will not willingly pay for it.

Seven ‘wastes’ in the process, that the customer will not pay for are –

1) reworking (correcting defects);

2) overproduction (you must assess demand as accurately as possible);

3) transportation (a cost the customer will not pay for willingly);

4) inventory (storage costs);

5) motion (costs incurred in moving machinery and conveying staff);

6) idle time (an employee or equipment doing nothing is still consuming resources); and

7) inefficiencies in the process itself (which is the focus of Six Sigma).

Lean Six Sigma attempts to reduce wastage alongside improving efficiency.