In psychology and sociology, a trust metric is a measurement of the degree to which one social actor (an individual or a group) trusts another social actor. Trust metrics may be abstracted in a manner that can be implemented on computers, making them of interest for the study and engineering of virtual communities, such as Friendster and LiveJournal.
Trust escapes a simple measurement because its meaning is too
subjective for universally reliable metrics, and the fact that it is a
mental process, unavailable to instruments. There is a strong argument
against the use of simplistic metrics to measure trust due to the
complexity of the process and the 'embeddedness' of trust that makes it
impossible to isolate trust from related factors. For a detailed
discussion about different trust metrics see.