ESTIMATING BORDER EFFECTS: THE IMPACT OF SPATIAL AGGREGATION
研究了贸易数据空间加总对引力模型估计的影响，发现加总导致边界效应异质性，大区域和国家边界效应更小，并用美国州级数据验证。
Abstract Trade data are typically aggregated across space. In this article, we investigate the sensitivity of gravity estimation to spatial aggregation. We build a model in which micro regions are aggregated into macro regions. We then apply the model to the large literature on border effects in domestic and international trade. Our theory shows that aggregation leads to border effect heterogeneity. Larger regions and countries are systematically associated with smaller border effects. We test our theory with aggregate and industry‐level trade flows for U.S. states. Our results confirm the model's predictions, with strong heterogeneity patterns.