Simultaneous spikes in global prices of many agricultural commodities in recent years have induced an interest in quantifying the degree of synchronisation of these movements. We suggest a conceptual framework explaining why temporally varying price synchronisation may happen and propose the concordance index for the empirical measurement of the incidence, symmetry and permanence of synchronisation. We establish that the index generates insights into time series dynamics which are complementary to those obtained from cointegration analysis. We illustrate the approach with an application for the co-movement in cyclical components of pig and cattle prices in three Latin American countries. The findings reveal moderate synchronisation levels which show asymmetric instabilities.

中文翻译：

---

衡量农产品价格的同步性：巴西、智利和乌拉圭的猪和牛价格周期的联动

近年来，许多农产品的全球价格同时飙升，引起了人们对量化这些运动同步程度的兴趣。我们提出了一个概念框架来解释为什么可能会发生随时间变化的价格同步，并提出了用于对同步的发生率、对称性和持久性进行实证测量的一致性指数。我们确定该指数产生了对时间序列动态的洞察，这些洞察与从协整分析中获得的互补。我们通过三个拉丁美洲国家的猪和牛价格周期性成分的联动应用来说明该方法。研究结果揭示了适度的同步水平，显示出不对称的不稳定性。