Multilateral methods are increasingly being used in the computation of official price indexes such as the consumer price index (CPI). This reflects the growing use of scanner data by statistical agencies and the fact that fixed-based or chained price comparisons perform poorly in this context. A range of multilateral approaches have been pursued by different statistical agencies. Yet, it can be shown that some of these methods, at least theoretically, could suffer from substitution bias. We investigate this as well as the drivers of chain drift. We adopt a simulation-based approach using actual scanner data prices with the corresponding quantities being generated assuming constant elasticity of substitution (CES) preferences. We find that most methods systematically deviate from the exact CES benchmark index. This is even the case for the superlative index methods, which should not exhibit substitution bias. Interestingly, we also find significant chain drift even in the exact CES indexes. We argue this reflects life cycle pricing and particularly run-out sales at the end of a product's life.

中文翻译：

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多边方法、替代偏差和链式漂移：一些实证比较

多边方法越来越多地用于计算官方价格指数，例如消费者价格指数 (CPI)。这反映了统计机构越来越多地使用扫描仪数据，以及基于固定或链接的价格比较在这种情况下表现不佳的事实。不同的统计机构采取了一系列多边方法。然而，可以证明其中一些方法，至少在理论上，可能会受到替代偏差的影响。我们调查了这一点以及链漂移的驱动因素。我们采用基于模拟的方法，使用实际的扫描仪数据价格，假设替代弹性 (CES) 偏好不变，则生成相应的数量。我们发现大多数方法系统地偏离了确切的 CES 基准指数。即使是最高级索引方法也是如此，它不应该表现出替代偏差。有趣的是，即使在确切的 CES 指数中，我们也发现了显着的链漂移。我们认为这反映了生命周期定价，尤其是产品生命周期结束时的销售量。