Customers have needs and requirements. A customer need establishes the relationship between the organization and the customer (example: I need (or want) an iPad). Requirements are those characteristics that determine whether or not the customer is happy. (Examples: a requirement is that the iPad is user-friendly, has to be fast in data storage and retrieval, etc.)
There are other requirements such as light-weight, long battery life and so forth. What we’re talking about here though with Six Sigma is things that you can measure on a continuous scale. You can measure user-friendliness on a Likert scale. You can measure the download/upload in megabits per second or load times in fractions of seconds. The fact that the iPad is lightweight is just a feature that doesn’t change and it isn’t something that you would really measure to make improvements.
