AUTHOR=Doreian Patrick , Mrvar Andrej 

TITLE=Delineating Changes in the Fundamental Structure of Signed Networks

JOURNAL=Frontiers in Physics

VOLUME=Volume 8 - 2020

YEAR=2020

URL=https://www.frontiersin.org/journals/physics/articles/10.3389/fphy.2020.00294

DOI=10.3389/fphy.2020.00294

ISSN=2296-424X

ABSTRACT=A fundamental problem for network analysis is the delineation of the fundamental structure of networks. Even more important is the delineation of changes in this network structure over time. We present a method for doing both for signed networks. The data come from the completed years of the Roberts US Supreme Court for the 2005 through 2018 terms. For the issues selected by the court for consideration in each  term, the justices vote on the decision that will be issued by the court. These votes are either to support a decision or to dissent from it. These votes can be recorded into a signed 2-mode network. While we examine these networks, our primary focus is on the 1-mode projection from the 2-mode network with the justices as units. Using signed relaxed structural balance blockmodeling, we establish the fundamental structure of the relations between justices for each of the terms. For 13 of the 14 terms considered, the criterion function for the blockmodels is zero. This structure changes in clear ways and shows that the conventional divide between conservative and liberal justices is overly simplistic.