“…Al-Molhem et al [68] conducted social network analysis to enhance the results of churn prediction models in the telecom domain using call detail records to construct a weighed graph representing the distance between two subscribers to calculate the centrality. The usage of marketing related variables, such as promotions offered to a customer, calls developed in a retention strategy, and helpdesk interactions, were applied by Verbeke et al [50] However, certain studies did not identify the features employed [9,12,18,22,25,42,48,67,70,73,85,87,88,97,98,99,107,110,112,113,116,119,122,127], which in some cases are related to the usage of more than one database. Idris et al [119] used two databases (orange and cell2cell).…”