4.1 Introduction

One of the most important success factors in designing superior service products is to know your customers. For a Six Sigma company, the design decision should be driven by the voices of customers. For the service industry, obtaining detailed customer data is even more important because maintaining customers' loyalty is extremely vital for the survival of a service institution. The customer survey is an essential tool that can yield information about customer expectations and customer satisfactions and assist in creating strategies for improvement.

Commercial enterprises use customer survey findings to formulate marketing strategies and design their products. Television and radio programs are evaluated and scheduled largely based on the results of consumer surveys. Libraries, restaurants, financial institutions, and recreational facilities use customer surveys to gather information about customer composition and customer desires.

Customer surveys of only a sample of customers are taken to learn about the whole population of a customer base. The sample may contain as few as 30 (a small sample) to as many as 30,000 or more (a very large sample) people. The data obtained on the survey are then analyzed. The survey method is based on sound statistical principles, and over 70 years of modern survey practices show that the predictions based on information from a survey of a relatively small sample are usually quite accurate.