Excellence in customer service is the hallmark of success in service industries and among manufacturers of products that require reliable service. But what exactly is excellent service? It is the ability to deliver what you promise, say the authors, but first you must determine what you can promise. Building on seven years of research on service quality, they construct a model that, by balancing a customer's perceptions of the value of a particular service with the customer's need for that service, provides brilliant theoretical insight into customer expectations and service delivery.

For example, Florida Power & Light has developed a sophisticated, computer-based lightening tracking system to anticipate where weather-related service interruptions might occur and strategically position crews at these locations to quicken recovery response time. Offering a service that customers expect to be available at all times and that they will miss only when the lights go out, FPL focuses its energies on matching customer perceptions with potential need. Deluxe Corporation, America's highly successful check printer, regularly exceeds its customers' expectations by shipping nearly 95% of all orders by the day after the orders were received. Deluxe even put U.S. Postal Service stations inside its plants to speed up delivery time.

Customer expectations change over time. To anticipate these changes, Metropolitan Life Insurance Company regularly monitors the expectations and perceptions of their customers, using focus group interviews and the authors' 22-item generic SERVQUAL questionnaire, which is customized by adding questions covering specific aspects of service they wish to track.

The authors' groundbreaking model, which tracks the five attributes of quality service -- reliability, empathy, assurance, responsiveness, and tangibles -- goes right to the heart of the tendency to overpromise. By comparing customer perceptions with expectations, the model provides marketing managers with a two-part measure of perceived quality that, for the first time, enables them to segment a market into groups with different service expectations.