53 Pages Posted: 23 Mar 2014 Last revised: 15 Mar 2017

Date Written: February 17, 2017

Abstract

This paper displays data from the US and its top 40 trading partners on the search volume of select keywords from before and after the surveillance revelations of June 2013, to analyze whether Google users' search behavior changed as a result. The surveillance revelations are treated as an exogenous shock in information about how closely users' internet searches were being monitored by the US government. Each search term was independently rated for its degree of privacy sensitivity along multiple dimensions. Using panel data, our results suggest that search terms that were deemed both personally-sensitive and government-sensitive were most negatively affected by the PRISM revelations, highlighting the interplay between privacy concerns relating to both the government and the private individual. Perhaps surprisingly, the largest `chilling effects' were not found in countries conventionally treated as intelligence targets by the US, but instead in countries that were more likely to be considered allies of the US. We show that this was driven in part by a fall in searches on health-related terms. Suppressing health information searches potentially harms the health of search engine users and, by reducing traffic on easy-to-monetize queries, also harms search engines' bottom line. In general, our results suggest that there is a chilling effect on search behavior from government surveillance on the Internet, and that government surveillance programs may damage the profitability of US-based internet firms relative to non-US-based internet firms.