… This is a relatively new phenomenon, but pollsters have increasingly found evidence of partisan nonresponse — that is, particular types of Republicans are just less likely to take surveys, so these voters’ opinions are not reflected in survey data. This was especially relevant in understanding Trump’s support, too, as many of these voters broke for him and other Republicans in 2020.
But why are some Republican voters more reluctant to take surveys? As the director of polling at the Cato Institute, I, as well as other pollsters, am studying this and currently have two working theories for why this is happening. First, Republicans are becoming more distrustful of institutions and society, and that may be extending to how they feel about pollsters. Second, suburban Republican college graduates are more likely to fear professional sanction for their views and are therefore self-censoring more, including in surveys. CONTINUED
Emily Ekins (Cato Institute), FiveThirtyEight