Advertisers and researchers use tools provided by advertising platforms to conduct randomized experiments for testing user responses to creative elements in online ads. Internally valid comparisons between ads require the mix of experimental users exposed to each ad to be similar across all ads....

This article proposes a framework for the analysis of attitudes to foreign trade policies that challenges the traditional skill-endowment approach. The traditional approach assumes informed individuals who calculate the costs and benefits of alternative policies. We propose that individuals lack...