Is there a strong link between your company's customer satisfaction or Net Promoter Score levels and the share of spending that customers allocate to your brand? We suspect that if we polled managers from virtually any firm, the consensus would be “Yes!”

Unfortunately, almost none of them would have the evidence to actually support this belief. Traditional metrics designed to gauge customers' perceptions of the brands that they use do a terrible job of correlating with customers' share of wallet levels. This is a serious problem.

For most firms, the greatest financial opportunity from improving satisfaction and loyalty is getting customers to allocate a greater percentage of their spending to a brand—far more than the impact of improved retention rates or referrals. Without the ability to link satisfaction to customers' share of spending, it is almost impossible for managers to determine what to do to improve customers' buying behaviors. Consequently, the return on efforts to improve the customer experience is frequently trivial, even negative.

Despite an abundance of books, articles, and speeches on the importance of the customer experience to business success (and a host of metrics that purport to guide managers to this success), to date there has been no easy-to-use system for managers to gauge performance that meaningfully links to customers' spending behaviors. As a result, “proof” of success has too often been limited to anecdotal evidence that seldom proves applicable to other companies.

This book fills that void. It provides a new and rigorously tested approach—the Wallet Allocation Rule—that is proved to link customer satisfaction and other commonly used metrics to share of wallet.

The Wallet Allocation Rule is at once a profound, award-winning Harvard Business Review–published thought leadership and a return to the fundamentals of business success from which managers stray at their peril. The practical principles detailed in this book provide managers with the tools they need to win where it counts most—in their customers' spending.

Henri Wallard

Deputy CEO, Ipsos

Chairman of Ipsos Loyalty, Ipsos MediaCT, and Ipsos Public Affairs

Ralf Ganzenmueller

CEO, Ipsos Loyalty