Structure and Tie Strengths in Mobile Communication Networks

Structure and Tie Strengths in Mobile Communication Networks J.-P. Onnela J. Saramäki J. Hyvönen A.-L. Barabási et al.

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Structure and Tie Strengths in Mobile Communication Networks 2007 PNAS / arXiv 10.1073/pnas.0610245104 physics/0610104 onnela2007-tie-strengths onnela2007-tie-strengths.txt, the project's staged copy da4c15edb7ef9df0eca7a4ce1cc89e1fadb2d3aa arxiv-open sociology

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0 spans located by searching the stored text for the quote's exact words, allowing any whitespace between them mechanism Quotation withheld because this record is not cleared for redistribution. tie strength and local topology in mobile communication networks Quotation withheld because this record is not cleared for redistribution. network-analysis network-analysis Quotation withheld because this record is not cleared for redistribution. mechanisms weak ties bridge otherwise-separate communities, so removing them fragments the network via a percolation-like phase transition (a societal-scale confirmation of Granovetter strength-of-weak-ties) Quotation withheld because this record is not cleared for redistribution. The reconstructed graph covers only mobile voice calls, not the full range of interactions between people. what this limits: every claim about social ties from this graph: THE MCG CAPTURES ONLY A SUBSET OF ALL INTERACTIONS BETWEEN INDIVIDUALS, [excluding] FACE-TO-FACE, EMAIL AND LANDLINE Quotation withheld because this record is not cleared for redistribution. The reciprocity requirement used to define a link may discard genuine social ties (false negatives). what this limits: the link definition: the reciprocity requirement INDUCES SOME FALSE NEGATIVES, I.E. SOME LINKS CORRESPONDING TO GENUINE SOCIAL INTERACTION MAY GO UNDETECTED Quotation withheld because this record is not cleared for redistribution. The data are a single-operator sample of the underlying national call network, not the whole population network. what this limits: any population-level reading: ALTHOUGH THE DATASET COVERS SOME SEVEN MILLION USERS, IT IS NEVERTHELESS A SAMPLE OF THE UNDERLYING PHONE CALL NETWORK - scale is not coverage Quotation withheld because this record is not cleared for redistribution. The strength of a social tie is measured as the total time two people spent on the phone. what this limits: any claim here about the strength of social ties: strength is defined as the aggregated duration of calls between two users, after one-way calls have been eliminated by a reciprocity requirement Quotation withheld because this record is not cleared for redistribution. The network studied is a stand-in for the communication network, and the paper says so. what this limits: conclusions drawn here about human communication: the mobile call graph is used as a proxy for the communication network between users, being skewed toward trusted interactions because people share mobile numbers only with those they trust Quotation withheld because this record is not cleared for redistribution. Three incompatible accounts of what drives tie strength were on the table before the measurement. what this limits: the interpretation of the correlation reported here: the paper sets out a dyadic hypothesis, in which strength is independent of the surrounding network, against the strength of weak ties hypothesis, in which strength increases with friendship-circle overlap Quotation withheld because this record is not cleared for redistribution. The conclusion sits between the positions rather than choosing one. what this limits: the finding as support for any single theory of tie strength: the authors state it is in part driven by local network structure, in contrast with both a purely dyadic view and a global view Quotation withheld because this record is not cleared for redistribution. percolation and network analysis (robustness, phase transitions) applied to a society-scale communication network Quotation withheld because this record is not cleared for redistribution. the same spreading simulation re-run on the SAME network with every tie strength replaced by the average, giving a constant transmission probability on every link eliminates: the network's TOPOLOGY as the explanation of the spreading result - the graph is held fixed and only the weights are flattened, so any difference must come from the distribution of tie strengths rather than from who is connected to whom · outcome (stated by the tagger, no quotation): held Quotation withheld because this record is not cleared for redistribution. tie strength tie strength Quotation withheld because this record is not cleared for redistribution. dyadic hypothesis dyadic hypothesis Quotation withheld because this record is not cleared for redistribution. global efficiency principle global efficiency principle Quotation withheld because this record is not cleared for redistribution. mobile call graph mobile call graph Quotation withheld because this record is not cleared for redistribution. betweenness centrality betweenness centrality Quotation withheld because this record is not cleared for redistribution. tie strength - AS AGGREGATED CALL DURATION: the sociological construct is measured by total air time between two people, over links that survive a reciprocity filter, so a strong tie here means many minutes and nothing else Quotation withheld because this record is not cleared for redistribution. what determines tie strength - THREE NAMED AND INCOMPATIBLE ANSWERS: a global efficiency principle in which strengths are optimised for overall flow, a dyadic hypothesis in which strength is independent of the surrounding network, and the strength of weak ties hypothesis in which it rises with friendship-circle overlap Quotation withheld because this record is not cleared for redistribution. the mobile call graph - AS A PROXY, AND A SKEWED ONE BY DESIGN: it stands in for the communication network and is biased toward trusted interactions, because people share mobile numbers only with individuals they trust Quotation withheld because this record is not cleared for redistribution. replicates → Granovetter weak-ties hypothesis (1973) Quotation withheld because this record is not cleared for redistribution. replicates → the strength of weak ties hypothesis (Granovetter) Quotation withheld because this record is not cleared for redistribution. contradicts → the dyadic hypothesis and the global efficiency principle Quotation withheld because this record is not cleared for redistribution. contradicts → the received account of weak ties as the conduits of novel information (Granovetter; Csermely) Quotation withheld because this record is not cleared for redistribution. millions — scale of the society-wide communication network studied Quotation withheld because this record is not cleared for redistribution. Phone-communication records of millions of users let the study examine a society-wide network's local and global structure together. Quotation withheld because this record is not cleared for redistribution. Social networks are robust to the removal of strong ties but fall apart in a phase transition if weak ties are removed, and this coupling significantly slows diffusion, trapping information in communities. Quotation withheld because this record is not cleared for redistribution. diffusion process diffusion process Quotation withheld because this record is not cleared for redistribution. local bridge local bridge Quotation withheld because this record is not cleared for redistribution. weak ties hypothesis weak ties hypothesis Quotation withheld because this record is not cleared for redistribution. bootstrap bootstrap about this quote: QUOTE RECOVERED FROM THE PAPER'S OWN CHARACTERS. 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