The theory of Six Sigma is to understand how much variability exists in the quality
of the products or services a company offers and to reduce the variability that results in customer dissatisfaction.
An example is a customer waiting in line to check out at a hotel.
Few travelers expect to be waited on immediately when they approach the checkout desk, so customer service in the hotel business does not have to be immediate.
However, few customers enjoy waiting in line to check out of the hotel because it is their intent to leave the hotel and get on with their travel.
There is an average time limit at which customers become dissatisfied. Let us say that time period is five minutes.
If the five minute mark is the break point between customer satisfaction and dissatisfaction, then the hotel realizes it must modify its checkout procedure if the customer wait will exceed five minutes.
Basically Six Sigma is a method of organizational change that uses statistical information (in this case, time in minutes) to execute actions (checking out hotel guests) to achieve a desired outcome (customer satisfaction).
The organization’s overall goal is to improve customer satisfaction by changing its practices on those matters most critical to pleasing customers.
Six Sigma is thus directed toward improving the processes that organizations use to meet their customers’ needs.