Hierarchical structure of the European countries based on debts as a percentage of GDP during the 2000-2011 period

TL;DR

This study analyzes the hierarchical relationships among European countries based on debt-to-GDP ratios from 2000 to 2011, revealing clustering patterns related to economic impact during the debt crisis.

Contribution

It introduces a hierarchical analysis of European countries' debt structures over time using MST and hierarchical trees, including statistical reliability assessments.

Findings

Eurozone economies form distinct clusters during the debt crisis

Hierarchical structures reveal temporal evolution of economic ties

Bootstrap techniques confirm link reliability

Abstract

We investigate hierarchical structures of the European countries by using debt as a percentage of Gross Domestic Product (GDP) of the countries as they change over a certain period of time. We obtain the topological properties among the countries based on debt as a percentage of GDP of European countries over the period 2000-2011 by using the concept of hierarchical structure methods (minimal spanning tree, (MST) and hierarchical tree, (HT)). This period is also divided into two sub-periods related to 2004 enlargement of the European Union, namely 2000-2004 and 2005-2011, in order to test various time-window and observe the temporal evolution. The bootstrap techniques is applied to see a value of statistical reliability of the links of the MSTs and HTs. The clustering linkage procedure is also used to observe the cluster structure more clearly. From the structural topologies of these trees, we identify different clusters of countries according to their level of debts and economic ties. Our results show that by the debt crisis, the less and most affected Eurozones economies are formed as a cluster with each other in the MSTs and hierarchical trees.