In contrast to international trade, it is still difficult to find regional trade statistics within a nation. Given that the gravity model continues to be very popular, we test two gravity-RAS approaches used for interregional trade estimation: a standard one and an extended version, which additionally estimates intra-regional flows. We assess the accuracy with the help of two measures and for different sectoral aggregation levels. For that, we use the survey-based 2005 interregional input–output table of Japan as a benchmark. Results show high overall accuracy levels for the standard approach, better than when using international data, albeit with heterogeneous errors for sectors and regions. We further find that the results of a multiregional input-output model are highly sensitive to the trade estimation approach and that errors slightly increase for increasing sectoral disaggregation levels. Results from an experiment based on a random number generator show how RAS influences results.

与国际贸易相反，仍然很难在一个国家内找到区域贸易统计数据。鉴于重力模型仍然非常流行，我们测试了用于区域间贸易估算的两种重力RAS方法：标准方法和扩展版本，它们另外估算了区域内流量。我们通过两种方法以及针对不同部门的汇总水平来评估准确性。为此，我们以日本基于调查的2005年区域间投入产出表为基准。结果显示，标准方法的总体准确性较高，尽管使用扇区和区域时存在异类错误，但优于使用国际数据时。我们进一步发现，多区域投入产出模型的结果对贸易估算方法高度敏感，而且随着部门分类水平的提高，误差会略有增加。基于随机数生成器的实验结果表明RAS如何影响结果。