Abstract We use data from the American National Election Studies from 1996 to 2016 to study the role of the internet in the 2016 U.S. presidential election outcome. We compare trends in the Republican share of the vote between likely and unlikely internet users, and between actual internet users and non-users. Relative to prior years, the Republican share of the vote in 2016 was as high or higher among the groups least active online.

Citation: Boxell L, Gentzkow M, Shapiro JM (2018) A note on internet use and the 2016 U.S. presidential election outcome. PLoS ONE 13(7): e0199571. https://doi.org/10.1371/journal.pone.0199571 Editor: Nicola Lacetera, University of Toronto, Rotman School, CANADA Received: March 25, 2018; Accepted: June 8, 2018; Published: July 18, 2018 Copyright: © 2018 Boxell et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. Data Availability: Data are available from the American National Election Studies (http://www.electionstudies.org/) for researchers who meet the criteria for access. The specific datasets used are listed in the references. The replication code (excluding the data) is provided in the supporting information files. Funding: JMS acknowledges funding by the Brown University Population Studies and Training Center (https://www.brown.edu/academics/population-studies/), which receives support from the National Institute of Health (Grant P2C HD041020). MG acknowledges funding from the Toulouse Network for Information Technology (http://idei.fr/contract/toulouse-network-information-technology-tnit) and the Stanford Institute for Economic Policy Research (https://siepr.stanford.edu/). LB acknowledges funding from the National Science Foundation (grant number: DGE-1656518) and the Institute for Humane Studies (https://theihs.org/). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript. Competing interests: I have read the journal’s policy and the authors of this manuscript have the following competing interests: M.G. is a member of the Toulouse Network of Information Technology, a research group funded by Microsoft, and has done paid consulting for Amazon. J.M.S. has, in the past, been a paid visitor at Microsoft Research and a paid consultant for FutureOfCapitalism, LLC. L.B. has written a research brief on this subject for the Cato Institute, for which he was paid. This does not alter our adherence to PLOS ONE policies on sharing data and materials.

Introduction Many have hypothesized that the internet and social media impacted the outcome of the 2016 U.S. presidential election. In a post-election interview, Hillary Clinton emphasized the role of social media in the election, citing fake news, Russian intervention, and Republicans’ success in “marrying content with delivery and data” [1]. Others have emphasized the Trump campaign’s use of data to target messages online [2]. There have been several attempts at examining these claims about the 2016 election empirically. Some argue that the internet is unlikely to have helped Trump because only a small percentage of Trump supporters use social media and because Trump did unusually well among the demographic groups least likely to use the internet [3]. Others show that while fake news was dominantly pro-Trump, it would have to be extraordinarily persuasive relative to other media technologies (e.g., TV ads) in order for it to have swayed the election [4]. We use data from the American National Election Studies (ANES) from 1996 to 2016 to study the role of the internet in the 2016 election outcome. Following closely the methodology used in a prior study of political polarization [5], we compare trends in the Republican share of the vote between likely and unlikely internet users, and between actual internet users and non-users. Relative to prior years, the Republican share of the vote in 2016 was as high or higher among the groups least active online. Under the assumptions that (i) the internet affects elections only by changing the partisan vote share among those active on the internet, (ii) the effects of the internet on voting behavior are identical across individuals, and (iii) no other time-varying factors affected the difference in Republican vote share between internet-active and internet-inactive groups, our findings imply that the internet was not a source of advantage to Trump. (See Model section of the S1 Appendix). Alternatively, our findings may be viewed as implying that, if the internet was a significant source of advantage to Trump, at least one of assumptions (i), (ii), or (iii) must be violated in a quantitatively significant way. We discuss this possibility in more detail in the concluding section.

Data We use data from the ANES [6–9], which is a nationally representative survey that asks various demographic and political questions. We use the ANES 1948–2012 Time Series Cumulative, 2008 Time Series, 2012 Times Series, and 2016 Time Series datasets. We use data from survey waves in presidential election years from 1996–2016, inclusive, and we restrict attention to face-to-face surveys, excluding internet-based surveys that were conducted in more recent years. Our calculations weight responses from 1996–2012 by the type-0, face-to-face survey weights and responses from 2016 by the post-election, face-to-face survey weights. Our outcome variable is the party that the respondent voted for in the most recent presidential election. We construct this variable from responses to “How about the election for President? Did you vote for a candidate for President? (IF YES:) Who did you vote for?” which are then coded as either Republican, Democratic, Other, or refusals for respondents who said they voted for a presidential candidate. Respondents who report not voting for a presidential candidate or who refuse to say who they voted for are excluded from our main analysis. We use three different measures of internet use. Our first measure, which we refer to as whether or not a respondent uses the internet, comes from responses to “Do you have access to the Internet or the World Wide Web [exc. 2008: (‘the Web’)]?” for 1996–2008 and “Do you or anyone in this household use the Internet at any location?” for 2012–2016. Our second measure, which we refer to as whether or not a respondent observed campaign news online, comes from responses to “Have you seen any information about this election campaign on (the Internet/the Web)?” for 1996–2004, “Did you read, watch, or listen to any information about the campaign for President on the Internet?” for 2008–2012, and whether respondents “heard anything about the presidential campaign” on “Internet sites, chat rooms, or blogs” for 2016. Our third measure, which we refer to as predicted internet access, comes from [5] and classifies respondents according to whether the respondent is in the top or bottom quartile in terms of the likelihood of having internet if they were a respondent in 1996, as predicted from the following covariates: age group, gender, race, education, and whether the respondent lives in the political south. Table 1 shows the regression used to construct the predicted internet measure. PPT PowerPoint slide

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larger image TIFF original image Download: Table 1. Predicted internet, 1996. https://doi.org/10.1371/journal.pone.0199571.t001 Separately for each measure of internet use, we exclude respondents with missing or non-valid responses (as defined by the ANES) to the questions needed to construct the measure. For the predicted internet measure in 2016, we also drop respondents whose response for education is in the “95. Other SPECIFY” category. Please see S1 Replication Code for exact details on the variables and samples used along with their construction.

Discussion Relative to his predecessors, Trump performed worse among the demographic groups most likely to use the internet and social media. These facts do not rule out the possibility that these technologies advantaged Trump. It is possible that each of the three assumptions stated in the introduction could be violated: It could be that content originating on social media was rebroadcast on traditional media such as cable television, and so persuaded non-internet users. It could be that those least active online are those who are most influenced by internet content when exposed to it. It could be that internet users would have been even less likely to vote for Trump absent new information technologies. If social media content was a decisive factor in Trump’s victory, factors such as these must have been quantitatively significant. Until we have more precise quantitative evidence on the role of these factors, we think our findings caution against assuming that new technologies played a large role in the 2016 election outcome.

Acknowledgments The American National Election Studies and the relevant funding agencies bear no responsibility for use of the data or for interpretations or inferences based upon such uses.