High-speed rail connectivity and supply chain information symmetry: insights from the bullwhip effect

This study investigates the role of improved transportation accessibility in mitigating supply chain information asymmetry from the perspective of the bullwhip effect. Based on panel data of 426 cross-city supply chains in China from 2003 to 2021, this study exploits HSR connections between upstream and downstream firms as a quasi-natural experiment that endows supply chains with information channels, and employs a staggered difference-in-differences model combined with specific lexicon-based text mining to evaluate the impact of HSR on the bullwhip effect. We document three main findings: (1) HSR connections reduce the bullwhip effect by 0.0975 standard deviations, corresponding to approximately 32.7 % of the average level. (2) The underlying mechanism is that HSR enhances face-to-face interactions and information disclosure quality between suppliers and customers, thereby facilitating the exchange of both soft and hard information and alleviating information asymmetry. (3) Supply chain length and digitalization serve as key moderators: chains of moderate length (approximately 300–1200 km) benefit more from HSR, while advanced digitalization may dampen HSR's role in information reconciliation under certain conditions. This study offers a region-wide strategy for mitigating the bullwhip effect, enriches the literature on HSR's economic externalities, and advances the application of Soft and Hard Information Theory in supply chain management.