The Ultimate Question 2.0: How Net Promoter Companies Thrive in a Customer-Driven World – by Fred Reichheld and Rob Markey
In this book, Fred and Rob expand on the original and modify the “S” in NPS to evolve from “score” to “system.” They realized a focus on the score was much too narrow and needed to move the thinking of the user to a system, where moving the needle was an outcome of doing the work to improve the experience first. Still good to read the first book to get a solid foundation of the research behind NPS.