Three items measure a person's continued patronage of a company due to the perceived difficulty, cost, and effort required to switch providers.
Verhoef, P. C., Franses, P. H., & Hoekstra, J. C. (2002). The effect of relational constructs on customer referrals and number of services purchased from a multiservice provider: Does age of relationship matter? Journal of the Academy of Marketing Science, 30(3), 202–216.
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