Using Search Results to Fight Piracy


With the growing consensus in the empirical literature that piracy harms sales, and emerging evidence that increased piracy can affect both the quantity and quality of content produced (here and here for example), governments and industry partners are exploring a variety of ways to reduce the harm caused by intellectual property theft. In addition to graduated response efforts and site shutdowns, Internet intermediaries such as Internet Service Providers, hosting companies, and web search engines are increasingly being asked play a role in limiting the availability of pirated content to consumers.

However, for this to be a viable strategy, it must first be the case that these sorts of efforts influence consumers’ decisions to consume legally. Surprisingly, there is very little empirical evidence one way or the other on this question.

In a recent paper, my colleagues Liron Sivan, Rahul Telang and I used a field experiment to address one aspect of this question: Does the prominence of pirate and legal sites in search results impact consumers’ choices for infringing versus legal content? Our results suggest that reducing the prominence of pirate links in search results can reduce copyright infringement.

To conduct our study, we first developed a custom search engine that allows us to experimentally manipulate what results are shown in response to user search queries. We then studied how changing what sites are listed in search results impacted the consumption behavior of a panel of users drawn from a general population, and a separate panel of only college aged participants.

In our experiments, we first randomly assigned users to one of three groups: a control group of users who are shown the same search results they would receive from a major search engine, and two treatment groups where pirate sites are artificially promoted and artificially demoted in the displayed search results. We then asked users to obtain a movie they are interested in watching, and to use our search engine instead of the search engine they would normally use. We observe what queries each set of users issued to search for their chosen movie, and surveyed them regarding what site they used to obtain the movie.

Our results suggest that changing the prominence of pirate and legal links has a strong impact on user choices: Relative to the control condition, users are more likely to consume legally (and less likely to infringe copyright) when legal content is more prominent in search results, and user are more likely to consume pirate content when pirate content is more prominent in search results.

By analyzing users’ initial search terms we find that these results hold even among users with an apparent predisposition to pirate: users whose initial search terms indicate an intention to consume pirated content are more likely to use legal channels when pirated content is harder to find in search results.

Our results suggest that reducing the prominence of pirate links in search results can reduce copyright infringement. We also note that there is both precedent and available data for this sort of response. In terms of precedent, search engines are already required to block a variety of information, including content from non-FDA approved pharmacies in the U.S. and content that violates an individual’s “right to be forgotten” in a variety of EU countries. Likewise, the websites listed in DMCA notices give search engines some of the raw data necessary to determine which sites are most likely to host infringing content.

Thus, while more research and analysis is needed to craft effective policy, we believe that our experimental results provide important initial evidence that users’ choices for legal versus infringing content can be influenced by what information they are shown, and thus that search engines can play a role in the ongoing fight against intellectual property theft.