We conduct a field experiment on a movie-recommendation platform to investigate whether and how online recommendations influence consumption choices. Using a within-subjects design, our experiment measures the causal effect of recommendations on consumption and decomposes the relative importance of two economic mechanisms: expanding consumers' consideration sets and providing information about their idiosyncratic match value. We find that the informational component exerts a stronger influence - recommendations shape consumer beliefs, which in turn drive consumption, particularly among less experienced consumers. Our findings and experimental design provide valuable insights for the economic evaluation and optimisation of online recommendation systems.

翻译：我们在一个电影推荐平台上进行了一项实地实验，以研究在线推荐是否以及如何影响消费选择。通过采用被试内设计，我们的实验测量了推荐对消费的因果效应，并分解了两种经济机制的相对重要性：扩大消费者的考虑集和提供关于其异质性匹配价值的信息。我们发现信息成分具有更强的影响力——推荐塑造了消费者的信念，进而驱动消费，特别是在经验较少的消费者中。我们的研究结果和实验设计为在线推荐系统的经济评估和优化提供了有价值的见解。