“Dark Money” and “Dirty Politics”: Are anonymous ads more negative?†

Many scholars have studied the use of negative advertising in campaigns and what motivates candidates and groups to run negative ads. Recent elections, however, have seen a dramatic increase in advertising by outside groups, particularly by so-called “dark-money” organizations, which do not disclose their donor information. This study questions whether dark-money groups are more likely to engage in negative advertising. By examining the more than 13,000 outside-group expenditures from the 2010 through the 2014 congressional elections, it finds that outside groups are, indeed, more likely to use negative ads when they conceal their donor information. Additionally, while liberal and conservative groups are roughly equally likely to use negative ads, conservative groups are most likely to use anonymously funded negative advertisements. This could be, at least in part, due to the support conservative groups receive from organized businesses, which generally seek to conceal their political activities from public scrutiny.