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many ego netwoks

Christophe Prieur,
Télécom ParisTech, dept. SES, I3

Res-Hist 3


31 oct 2015

Many ego networks

Example of app.algopol

  • 15 000 respondents
  • Facebook friends network

Large networks

  • Millions of nodes
  • Each node comes with its ego network


The ethnographic way

ego makes a list

  • contacts
  • who knows whom

Face-to-face intervews with ego

Networks from Granjon et al., 2007

Local characteristics

  • Personal network of a node ego :
    • ego + contacts + their contacts
    • links between these nodes
  • Local computations :
    • nb. nodes
    • nb. links
    • nb. triangles with ego
    • nb. triangles
    • nb. squares
  • For each node of a very large network
    (possibly [mb]illions of nodes)

The systematic way


Same characteristics

  • 7 neighb, 40 nodes, 55 links

    55,000 such profiles among 3M

  • 3 triangles with ego, 13 total, 55 squares

    only these two

With information on interactions

Aggregating indicators:
The example of density


Raux & Prieur, 2011

Close ties

When new ties appear

close tie
far tie

Building one's network

Two nodes with the same final degree

mainly close neighbors
many far neighbors


with Bidart, Degenne, Grossetti

Weddings in Buenos Aires (1620-1840)

  • all weddings at the cathedral since its creation
  • 14 000 wedding certificates

Algopol: a mixed research framework

  • in collaboration with CSA poll agency
  • a sample of 880 representative internet users
  • 15 000 respondents
  • large-scale personal network analysis
  • ethnographic interviews

Facebook ties

talking religion or politics?

A Facebook app

data-based interviews