Red Sea shipping disruptions and the sensitivity of connectivity estimates
Kızıldeniz'deki denizcilik aksamaları ve bağlantılılık tahminlerinin duyarlılığı
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Abstract
Attacks on merchant ships in the Red Sea from November 2023 diverted many Asia–Europe liner services around the Cape of Good Hope. We estimated the effect of the crisis on the UNCTAD Liner Shipping Connectivity Index (LSCI) of three Eastern Mediterranean gateway countries, Egypt, Türkiye and Greece, using synthetic difference-in-differences (SDID) with nine donor countries not tied to the Suez route and placebo-in-space inference. All data were retrieved live from the open GOMD platform by a notebook that stops when a series is missing. With a pre-period of February 2019–August 2023 (19 quarterly observations) and a post-period of February 2024–May 2026 (10 observations), SDID estimates were positive for Egypt (+0.135 log points, about +14%) and Türkiye (+0.151, about +16%) and negative for Greece (−0.081, about −8%), with placebo p-values of 0.2, 0.2 and 0.4. The estimates changed little with the regularisation parameter, and unit weights were nearly uniform. Plots of observed and synthetic series showed that the LSCI of Egypt and Türkiye was already rising steeply before the crisis, so the full-period averages carry a pre-existing divergence. A short-window comparison of August 2023 with the first half of 2024 gave connectivity changes relative to the donor mean of −6.2% for Egypt (p = 0.20), −1.4% for Türkiye (p = 0.70) and −7.1% for Greece (p = 0.10). The direction agrees with the fall in Suez Canal transits reported by UNCTAD, but with nine donors the evidence remains weak. We also report Marine Regions EEZ polygon areas for the littoral states and show how the notebook handles a jurisdiction series that has not yet been loaded. The study illustrates simple safeguards for platform-based causal claims.
Keywords
Red Sea crisis; Liner Shipping Connectivity Index; Synthetic difference-in-differences; Placebo inference; Parallel trends; Suez Canal; Eastern Mediterranean; Maritime jurisdiction
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