In Six Sigma we’re taught reducing variance is a good thing but is this really always the case?

Take currency for example. In the US all paper currency is the same size and the same color. By reducing variance I’m sure the US Mint has saved costs by having a standardized ink color, standardized cutting machines, etc. However, how does this benefit me as a user? When looking at a $5 and $10 bill twenty feet away, most people can not tell the difference. How many times have you had to thumb through your wallet to find the correct bill or worried you gave someone an incorrect note (or been accused of giving back incorrect change if you’ve been on the receiving end)?

Now compare the US currency with Australian currency. Each denomination of paper money is a slightly different size and color (note: while there are extra upfront costs to the process, they are greatly offset by reduced printing demand as the result of an applied plastic coating.).Essentially the country has error proofed (i.e. Lean manufacturing) its currency to the end user.

The point I’m trying to make is that sometimes in Six Sigma we focus so hard on reducing variance to cut costs that we overlook characteristics deemed critical to quality by the end user. Even though costs have been reduced, underlying problems still exist, leaving the customer to view the product service of sub par quality.By introducing variance as a possible solution, one may be able greatly improve customer satisfaction.