Where does tie strength collide?

The strength of a dyadic tie, which Granovetter defined as a combination of the amount of time, the emotional intensity, the intimacy, and the reciprocal services that characterise a relationship between two people. His 1973 The Strength of Weak Ties argued that weak ties are disproportionately likely to be bridges between otherwise disconnected clusters, so novel information and opportunities travel across them rather than through the redundant strong ties inside a close-knit group. The 1983 revisit gathered a decade of evidence and refined the claim. The referent is a property of a relationship, and the paradox is that the weak ones, not the strong ones, do the work of holding a society together.[1][2]

Unit

The strength of a relationship between two people

Recovery means

Not applicable

Measured by

Rated by time spent together, emotional intensity, intimacy, and reciprocal services

Tie strength read as a weighted property of an edge in a graph, so a social network is no longer a set of present-or-absent links but a fabric of connections of graded intensity. Onnela and colleagues' 2007 Structure and tie strengths in mobile communication networks put a weight on each edge from the volume and duration of calls between two people, and tested Granovetter's hypothesis on a network of millions: strong ties sat inside communities and weak ties ran between them, and removing the weak ties fragmented the whole network faster than removing the strong ones. The referent is a number on an edge, estimated from communication records rather than from a survey.[3]

Unit

A weight on an edge between two nodes in a graph

Recovery means

Not applicable

Measured by

Derived from the aggregate volume and duration of communication between two people

Tie strength as it governs how people actually find work, where the surprising result is that jobs are more often reached through weak ties, acquaintances rather than close friends, because acquaintances move in different circles and carry information a person's close contacts already share. Granovetter's Getting a Job interviewed professional and managerial workers who had recently changed jobs and found that those who heard about the position through a personal contact most often heard it from someone they saw only occasionally, not from a close friend. The referent is the same relational strength, now indexed by how recently and how often two people were in touch, and read against whether a contact produced a job.[5]

Unit

The strength of the contact who supplied a job lead

Recovery means

Not applicable

Measured by

Reported frequency and recency of contact, read against whether the tie produced a job

Tie strength as the channel for knowledge inside an organisation, where the useful distinction is between searching for knowledge and transferring it. Hansen's 1999 The Search-Transfer Problem followed new-product projects across the subunits of a large electronics company and found that weak ties between units sped up the search for where useful knowledge lived, but slowed its transfer when that knowledge was complex, because moving something intricate takes the repeated, effortful interaction that only a strong tie sustains. The referent is the same tie strength, and its value flips with the task: weak for finding, strong for carrying what is hard to codify.[4]

Unit

The strength of the tie carrying knowledge between subunits

Recovery means

Not applicable

Measured by

Reported closeness and frequency of interaction between units, read against project search and completion time