This paper studies monetary policy design in small open economies with cross-border and input–output linkages. We derive the divine coincidence (DC) Phillips curve linking the output gap to a DC index that weights each sector’s inflation by sectoral contents in domestic consumption and exports, and of domestic labor. Output gap targeting can be implemented by stabilizing the DC index, which assigns larger weights to sectors that supply more inputs directly or indirectly to domestic output and face larger expenditure-switching effects. Disregarding openness or treating the economy as one sector overemphasizes inflation in sectors that export directly or indirectly, and underemphasizes inflation in sectors facing large expenditure-switching effects. We quantify our theoretical results using the World Input-Output Database, showing that the Phillips curves are steeper in open than closed economies, and that output gap targeting is near-optimal as in closed economies and outperforms alternative policies ignoring cross-border or input–output linkages.

本文研究了具有跨境联系和投入产出关联的小型开放经济体中的货币政策设计问题。我们推导出了“神圣巧合”菲利普斯曲线，该曲线将产出缺口与一个“神圣巧合指数”联系起来；该指数依据各部门在国内消费、出口中的份额以及国内劳动含量，对各部门的通货膨胀率进行加权。盯住产出缺口可通过稳定该指数来实现，该指数赋予那些直接或间接为国内产出提供更多投入、且面临较大支出转换效应的部门以更高的权重。若忽视经济开放性或将经济体视为单一部门，往往会过度强调直接或间接出口部门的通胀，而低估面临较大支出转换效应部门的通胀。利用世界投入产出数据库，我们对理论结果进行了量化分析。结果表明：相较于封闭经济体，开放经济体中的菲利普斯曲线更为陡峭；此外，与封闭经济体情形类似，以产出缺口为目标的政策接近最优，且优于那些忽视跨境联系或投入产出关联的替代性政策。