近日，浙江大学中国农村发展研究院、公共管理学院阮建青教授、蔡青文博士生、金松青教授合作撰写的学术论文Impact of COVID‐19 and Nationwide Lockdowns on Vegetable Prices: Evidence from Wholesale Markets in China，被国际农经领域Top期刊美国农业经济（American Journal of Agricultural Economics）录用，并于2021年2月22日在线发表。
该文是AJAE组织的“COVID‐19, Food, Environment, and Development”专题论文之一。新冠肺炎疫情是现代史上影响最为深重的一次重大突发公共卫生事件，对全球经济产生了巨大冲击。中国为防控疫情而采取的公共卫生安全事件一级应急响应，有效地阻断了病毒传播，但在短期内也对农产品市场产生了冲击。该文利用中国151个农产品批发市场的日度蔬菜价格数据，采用断点回归和双重差分模型，实证研究了中国应对新冠疫情所采取的严格管控政策对蔬菜价格的影响。研究发现，严格管控政策在短期内造成了蔬菜价格的急速、大幅上升，在第4周左右价格达到最高峰，但随后价格开始回落，到第11周左右价格回到正常水平。该文进一步验证了造成蔬菜价格剧烈波动的主要原因是供应链的中断。基于实证研究结果，该文提出了相应的政策建议：在突发公共卫生事件导致的严格管控政策时，对于生活必需的生鲜农产品，在产地与消费地之间，应采用灵活性的管控政策，保障生鲜农产品的流通；建设区域性的冷藏设施也有助于未来应对类似事件的影响；政府在重大公共卫生事件中，对贫困人口的救助，应该优先安排资金帮助他们降低因蔬菜等食品价格大幅上涨而造成的额外经济负担。
论文摘要如下：In this paper, we employ a combination of time regression discontinuity design method (T‐RD) and the difference‐in‐difference method (DID) to identify and quantify the causal effects of the strict lockdown policy on vegetable prices using multiple‐year daily price data from 151 wholesale markets of Chinese cabbage. We find that the lockdown policy caused a large and immediate surge in price and price dispersion of Chinese cabbage, though they fluctuated smoothly for the same period in normal years. The DID results further show that the price surge peaked in the fourth week of lockdown but gradually came down to the level of a normal year by week 11. However, the price rose again (though to a much smaller extent) in response to the resurgence of COVID‐19 in a few provinces in early‐mid April but quickly returned to the normal level in week 15 when the lockdown measures were largely removed. We also find that the supply chain disruption is the driving factor for the price hike. Policy implications are drawn.
