Economic theory posits that consumers’ response to technological innovations in distribution of cultural goods may have both positive and negative effects on the sales of these goods. Access to unauthorized cultural content – often referred to as “online piracy” – may reduce demand for the authorized distribution through substitution or raise it (through complementarity and similar effects). The empirical evidence speaks to both positive and negative correlation between unauthorized distribution and authorized sales. We review and discuss the accomplishments in the field so far and provide a quantitative analysis of the empirical literature, the meta-analysis. While numerous and interesting measures and methods have been developed, estimating reliable causal effect remains a challenge. There are also substantial differences between film and music industry. On the whole the literature fails to reject the null hypothesis of no effects on sales.

经济学理论认为，消费者对文化产品分配中的技术创新的反应可能对这些产品的销售产生积极和消极的影响。获得未经授权的文化内容（通常称为“在线盗版”）可能会通过替代或增加（通过互补和类似作用）减少对授权发行的需求。经验证据表明，未经授权的发行与授权的销售之间存在正相关和负相关。我们回顾并讨论了迄今为止该领域的成就，并提供了对实证文献，荟萃分析的定量分析。尽管已开发出许多有趣的措施和方法，但可以估算出可靠的因果关系效果仍然是一个挑战。电影和音乐产业之间也存在实质性差异。总体而言，文献未能拒绝对销售无影响的零假设。