|   | CMU-ISRI-05-117 Institute for Software Research International
 School of Computer Science, Carnegie Mellon University
 
    
     
 CMU-ISRI-05-117
 
 Relating Network Topology to the Robustness of Centrality Measures
 
Terrill L. Frantz, Kathleen M. Carley 
May 2005  
Center for Computational Analysis of Social and Organizational SystemsCASOS Technical Report
 
CMU-ISRI-05-117.pdf
 
Keywords: Social networks, data error, centrality, robustness, sensitivity, simulation This paper reports on a simulation study of social networks that 
investigated how network topology relates to the robustness of 
measures of system-level node centrality. This association is 
important to understand as data collected for social network 
analysis is often somewhat erroneous and may -- to an unknown degree --
misrepresent the actual true network. Consequently the values 
for measures of centrality calculated from the collected network data 
may also vary somewhat from those of the true network, possibly leading 
to incorrect suppositions. To explore the robustness, i.e., sensitivity, 
of network centrality measures in this circumstance, we conduct 
Monte Carlo experiments whereby we generate an initial network,
perturb its copy with a specific type of error, then compare the 
centrality measures from two instances. We consider the initial 
network to represent a true network, while the perturbed represents 
the observed network. We apply a six-factor full-factorial block 
design for the overall methodology. We vary several control variables 
(network topology, size and density, as well as error type, form and 
level) to generate 10,000 samples each from both the set of all 
possible networks and possible errors within the parameter space. 
Results show that the topology of the true network can dramatically 
affect the robustness profile of the centrality measures. We found 
that across all permutations that cellular networks had a nearly 
identical profile to that of uniform-random networks, while the 
core-periphery networks had a considerably different profile. 
The centrality measures for the core-periphery networks are highly 
sensitive to small levels of error, relative to uniform and cellular 
topologies. Except in the case of adding edges, as the error increases, 
the robustness level for the 3 topologies deteriorate and ultimately 
converges.
 
24 pages 
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