Experimental Design Details
We randomize respondents into one of three conditions: "excuse", "no excuse", and "control".
We provide respondents in the "excuse group" and the "no excuse group" with information about a recent study (Lott 2018) that finds that undocumented immigrants in Arizona commit crimes at substantially higher rates than comparable US citizens. We tell participants that they will have the opportunity to authorize a donation to Fund the Wall (www.fundthewall.com), an organization that supports the proposed US-Mexico border wall, and that their individual donation decision will be published on a website that we create (such that others from their city may see their decision). Participants in the "excuse" and "no excuse" groups are shown a screenshot of the website and see that the page contains information about the Lott study, allowing us to hold second-order beliefs (beliefs about what website visitors will know) constant. Participants in the control group see a screenshot of the website, but they do not see any information about the Lott study.
The key treatment varies the availability of an "excuse" for donating: that is, whether the website makes it clear that respondents knew about the Lott study prior to donating. Our main hypothesis is that when respondents know that website visitors will know that they were informed about the Lott study prior to donating (the "excuse group"), they are more likely to donate than when respondents believe that website visitors will believe that they were not informed about the Lott study prior to donating (the "no excuse group"). We also hypothesize that participants in the "excuse" group will be more likely to donate than participants in the control group.
We will then examine results separately by political orientation. We expect higher mean donation rates among Republicans than among Independents, and higher mean donation rates among Republican-leaning Independents than Democrat-leaning Independents. However, we may also find a stronger treatment effect on Independents, given that the relevant "audience" for their donation decision -- acquaintances and/or others whose opinion they care about -- may be less likely to approve of the donation decision. In contrast, Republicans may expect a larger share of their acquaintances to approve of the donation decision even in the absence of an excuse, which may generate a weaker treatment effect.
We will also examine heterogeneity by the 2016 Republican vote share of the respondent's county, though the direction of the heterogeneity is a priori ambiguous. On one hand, respondents who privately want to donate and who live in majority Democrat areas might have greater need for an excuse, given that a larger share of their audience might disapprove of the donation in the absence of an excuse. On the other hand, these same respondents may be those who are least sensitive to social image concerns surrounding their political views, given that they have chosen to live in areas where the majority of the population does not share their political affiliation; this may generate a weaker treatment effect.
Lott, John R., Undocumented Immigrants, U.S. Citizens, and Convicted Criminals in Arizona (February 10, 2018). Available at SSRN: https://ssrn.com/abstract=3099992 or http://dx.doi.org/10.2139/ssrn.3099992