SVI is a systems model for social network situations that cannot easily be explicitly measured because of the complexity of interactions impacting user behavior. SVI can be used as a substructure or framework for isolating portions of complex social phenomena for addressing "why and how?" In this case under study, undercover police officers act under risky and confusing conditions in which they are required to compose accurate and swift judgments under extreme pressure. They must make alliances with "bad guys," operate within the law, assess validity of "bad guy" information (accounting for the threats and pressures on the "bad guy."
The elements of the model (which vary from case to case) are of two sorts: diachronic and synchronic -those that remain stable across time; and those that change according to time and circumstances. For instance, a criminal's given name, height, and last known address are reasonably stable or diachronic; a criminal's behaviors are likely to be strongly influenced by other circumstances, that is, they are synchronic. Knowing a criminal's name is not often likely to be adequate information to put the undercover police officer into a position to make an arrest. Knowing how a criminal might react under certain circumstances, may be more useful in making an arrest.