A customer portfolio will not yield maximum value for the firm if all means by which customers generate value are not taken into account (Kumar, V. (2013)). Customer Referral Value (CRV), Customer Knowledge Value (CKV), and Customer Influence Value (CIV) are contributions in need of consideration. However, there are other metrics of indirect value: Customer Engagement Value, Employee Engagement Value, Customer Brand Value, Business Reference Value, Salesperson Lifetime Value, and Donor Lifetime Value. Research is being continually conducted to uncover more and more facets of these metrics.
Kumar, V. (2013), Profitable Customer Engagement: Concept, Metrics, and Strategies. New Delhi, India: Sage Publications.