Hayes, B. E. (2009). Beyond the ultimate question: A systematic approach to improve customer loyalty. Quality Press. Milwaukee, WI.
Beyond the Ultimate Question includes a comprehensive review of the Net Promoter® Score (NPS). The author challenges the claims of the NPS developers and presents a more comprehensive method of measuring customer loyalty. It turns out that you need more than a single question to understand customer loyalty.
Improving customer loyalty relies on more than asking a single question. Customer experience management (CEM) programs have many moving parts, each contributing to the success of the program. The book includes best practices of CEM programs. Through a systematic study comparing loyalty leaders and loyalty laggards, I identified the steps companies need to undertake to create an effective CEM program. You need to look beyond simple metrics and improve all aspects of your CEM program. Read how Oracle and Akamai structure their customer feedback programs. Buy book.