In their model, the constructs of word-of-mouth sender’s expertise, word-of mouth
receiver’s expertise, and word-of-mouth receiver’s perceived risk are categorized
under noninterpersonal forces and the constructs of tie strength between word-of-mouth
sender and receiver and word-of-mouth receiver’s word-of-search activity are sorted
under interpersonal forces. Under this schema, three relationships are proposed: the
effects of interpersonal and noninterpersonal forces on the service purchase decision and
the effects of noninterpersonal forces on interpersonal forces.