6. Conclusion and discussion
This study investigates an issue critical to the success of referral marketing programmes: how can a group of customers be identified who are most influential and can affect the largest number of potential customers through word-of-mouth. Previous research is generally design- and technology-oriented and use simulationbased methods to simulate influence spread over networks. Using a unique data set composed of both communication data and referral behaviour data, this study investigates whether the algorithms based on influence propagation simulations perform well in terms of identifying the most influential individuals in the network and estimating their resulting influence spread. The results show that limiting the decision support method for finding top influencers to simulations leads to overestimations of the actual influence spread and resulting product adoption. The best results are attained when referral data is used for selecting top influencers. Unfortunately, it is not that common yet for organisations to capture data about their customers’ referral behaviour. In that case, a measure of tie strength between individuals should be incorporated in the selection method as this leads to a larger influence spread. Next to that, the results also prove that it is important to not just look at the influence of the targeted customers, but also at the influence of their connections. If the connections of the most influential customers are not willing to spread word-of-mouth, there is no use in targeting these customers with a marketing campaign since the influence will not spread very far. Overall, this study shows the value of a referral behaviour detection process. A decision support system for selecting the most influential customers based on referral data allows companies to identify their most influential customers of whom the influence spread will trigger the largest cascade in product adoption. Fortunately this kind of data is becoming easier to obtain thanks to the widespread use of social media. Hence, also other organisations that possess any kind of data related to referrals or recommendations and wanting to reach a large audience can benefit from the approach suggested in this paper. In case no referral behaviour data or proxy data thereof is available, the simulation methods based on network data are already valuable and succeed in identifying influencers in a social network, although less so than those based on referral data.