INTRODUCTION TO LEGAL NETWORK ANALYSIS

Version 0.1 (November 2023)

AUTHORS

• Gustavo Arosemena
• Gijs van Dijck
• Roland Moerland

LICENSE

This textbook is released under a CC BY license. This license lets you distribute, remix, adapt, and build upon our work, even commercially, as long as you credit us for the original creation.

Work in progress, do not cite or share

Welcome to this introduction in Legal Network Analysis. The aim of this introduction is to provide you with a theoretical and practical understanding of what network analysis is, what it can be used for in the context of legal research, and how it can be applied.

The theory will be discussed and illustrated by means of practical examples and sometimes exercises. We try to accommodate readers with different levels of proficiency in coding:

• If you have no coding (in Python) experience, you can read the PDF (or the notebook) and simply skip the code that is displayed.
• If you have experience with running code (e.g. in Jupyter Notebook or VScode), you can execute the code. We have entered the code for you, which means you only have to run the code.
• If you have experience with Python, you may download the Jupyter Notebook file and alter the code.

The textbook aims to introduce network analysis to legal scholars in a comprehensive and practical way. If you are interested in more background information regarding networks, their analysis and the graph theory underlying it, please feel free to consult the books listed below. We selected publications that are accessible when you are not yet versed in network analysis.

Networks:

• Newman, M. (2018). Networks. London: Oxford University Press.

(Social) Network analysis:

• John, S. (2017). Social Network Analysis. Sage.
• Robins, G. (2015). Doing social network research. Routledge.
• Scott, J. and Carrington, P.J. (2011). The SAGE handbook of Social Network Analysis. Sage
• Tsvetovat, M., & Kouznetsov, A. (2011). Social Network Analysis for Startups: Finding connections on the social web. O'Reilly.

Graph theory:

• Wallis, W. D. (2007). A beginner's guide to graph theory. Springer.
• Rahman, M. S. (2017). Basic graph theory. Springer.
• Steen, M. R. van. (2010). Graph theory and complex networks: An introduction. Maarten van Steen.

We, the authors, hope you will enjoy our introduction to Legal Network Analysis. We are always open to feedback, suggestions, and help. You can reach us at law-techlab@maastrichtuniversity.nl.

The code-part of the textbook is done exclusively in NetworkX. Since this library is pure python, it is easier to read its source code and that transparency matters for understanding. Faster libraries are available for those who need them, but that remains for the reader to explore.

For dependencies (besides the usual stuff) make sure you have up to date versions of:

• networkx
• pydot
• text-distance
• scipy

Chapters

Welcome

1. Network Analysis: An Introduction

2. Network Properties

3. Network Centrality

4. Community Detection

5. Data Collection and Data Preparation

6. Software

Appendix 1 Getting data into NetworkX

Appendix 2 Text Similarity Networks

Appendix 3 Normalization

Appendix 4 Vector Scaling and Normalization