Consumer-facing companies in developed economies have experienced little to no growth since the global recession of 2008. As a result, the smartest of the bunch are now increasingly looking outward, trying to spur growth by turning to new sources of customer insight-including 'implicit' data such as biometrics, 'structured' batches of Big Data such as online behaviour and 'unstructured' data such as social media and call centre conversations. They provide advice for re-wiring the customer insight function in an organization.

You are a marketing director with $5 million to invest in customer acquisition and retention. Which customers do you acquire, and which do you retain? Up to a point, the choice is obvious: Keep the consistent big spenders and lose the erratic small ones. But what about the erratic big spenders and the consistent small ones? It's often unclear whether you should acquire or retain them and at what cost. Businesses have begun dealing with unpredictable customer behavior by following the practices of sophisticated investors who own portfolios comprising dozens of stocks with different, indeed divergent, histories and prospects. Each portfolio is diversified so as to produce the investor's desired returns at the particular level of uncertainty he or she can tolerate. Customers, too, are assets--risky assets. As with stocks, the cost of acquiring them is supposed to reflect the cash-flow values they are likely to generate. The authors explain how to construct a portfolio based on the notion that a customer's risk-adjusted lifetime value depends on its anticipated effect on the riskiness of the group it is joining. The concept of risk-adjusted lifetime value has a transforming power: For companies that rely on it, product managers will be replaced by customer managers, and the current method of accounting for profit and loss--which is by product--will be replaced by one that determines each customer's P&L. Once adjusted for risk, those P&Ls will become the firm's key performance and operational metric.