Vol. 12 No. 2 (2026)
June 2026

Articles

Core-periphery structures in global agricultural gross and value added trade networks

Published 2026-06-30

  • Dominika Brózda-Wilamek
    • ,
  • Aleksandra Nacewska-Twardowska

Dominika Brózda-Wilamek
University of Lodz

Aleksandra Nacewska-Twardowska
University of Lodz

Abstract

Objective: This study aimed to identify and explain the structural differences of global agricultural trade networks, depending on the trade metric applied i.e., gross exports (EXGR) versus domestic value-added embedded in foreign final demand (FFD_DVA). By applying the core-periphery framework, we evaluated the degree of hierarchy, structural coherence, and temporal stability of core-periphery patterns within trade relationships between countries from 2011 to 2020.

Research Design & Methods: The analysis employed social network analysis (SNA) techniques, incorporating both the discrete and continuous versions of the core-periphery model, to identify structural roles within agricultural trade networks. The study relied on OECD TiVA data for value-added trade flows and constructs directed, weighted trade networks for EXGR and FFD_DVA separately. We calculated key SNA metrics, such as the final fitness index, coreness scores, the Gini coefficient, and heterogeneity.

Findings: The FFD_DVA network showed a much stronger fit to the ideal core–periphery structure than the EXGR network. China and the United States consistently formed the core, although their relative positions varied by metric. The FFD_DVA network became more stable over time and more hierarchical, confirming that value-added measures better reflect the structure of global agricultural trade.

Implications & Recommendations: Value-added metrics should be prioritised in assessing trade dependencies and risks, as they reveal structural patterns not visible in gross flows. Policy makers and researchers should apply value-added diagnostics to better identify vulnerabilities and understand the organisation of global agri-food supply chains.

Contribution & Value Added: The study offers a rare direct comparison of EXGR and FFD_DVA networks using identical core–periphery methods. It introduces a compact, multi-metric framework for analysing trade structures and demonstrates the added value of incorporating value-added data into agricultural trade research.

Keywords

social network analysis, core-periphery model, value-added trade, agricultural trade network, global value chains

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Author Biography

Dominika Brózda-Wilamek

PhD, Assistant Professor at the Department of International Business and Trade at University of Lodz. Her research interests include social network analysis, with a particular interest in foreign direct investment and cross-border merger and acquisitions.

Aleksandra Nacewska-Twardowska

PhD, Assistant Professor at the Department of International Business and Trade at University of Lodz. Her research interests include international trade, global value chains, value added trade, and visual analysis of trade networks.

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