Logistics Performance and Bilateral Trade Asymmetries: Evidence from Türkiye’s Trade with Germany, Bulgaria, and Romania

This study examines the determinants of bilateral trade asymmetries between Türkiye and its three main EU partners—Germany, Bulgaria, and Romania—over 2002–2024. Within the gravity framework, bilateral symmetry in trade data implies that reported exports should equal partner imports (Xᵢⱼ = Mⱼᵢ). Deviations from this condition reflect systematic distortions caused by valuation practices, institutional gaps, and crisis-induced disruptions. This study employs a fixed-effects panel framework to identify the structural and contextual determinants of mirror−data asymmetries in Türkiye–EU trade. Using HS2−level mirror statistics from TÜİK and Eurostat, three asymmetry measures—the Bilateral Asymmetry Index (BAI), Absolute Logarithmic Difference (ALD), and Relative Symmetry Index (RSI)—are estimated through a fixed-effects panel model. Results show that a one−unit improvement in logistics performance (LPI) reduces asymmetry by approximately 0.17 points (p < 0.01). Maritime connectivity (LSCI) shows a small but statistically significant positive coefficient, while exchange rate volatility remains insignificant. The effects of global crises are heterogeneous: the 2008 financial crisis significantly increases asymmetry (+0.07, p < 0.01), whereas COVID−19 is associated with a reduction in asymmetry (−0.04, p < 0.01). The interaction between LPI and crisis periods is negative and significant (−0.03, p < 0.05), confirming that a stronger logistics capacity buffers crisis-induced reporting gaps. Country-specific results reveal that Romania drives much of the variation (within−R2 = 0.26), while Germany remains largely insulated from crisis effects. The findings highlight that deviations from bilateral symmetry are driven by structural and institutional factors rather than random error. Policy recommendations stress harmonized customs valuation, digital logistics integration, and enhanced Türkiye–EU statistical coordination to strengthen trade data reliability and crisis resilience.