Supplementary files for "How we think about the political stances of others: evidence on projection from Canada, Germany, and the UK"

Supplementary files for article "How we think about the political stances of others: evidence on projection from Canada, Germany, and the UK"What leads people to assume that others are more or less similar to them ideologically? To answer this question, this article uses original data from three multi?party democracies to analyse respondents’ assumptions about the ideological proximity of hypothetical voters. In doing so, it focusses on an underexamined psychological mechanism in political science research – projection onto in-group members – with the aim of extending our understanding of the factors shaping second-order political beliefs. The article empirically assesses the impact of this mechanism, using an original survey experiment fielded in Canada, Germany, and the United Kingdom to examine the effect of shared partisanship and overlapping demographic markers on presumed ideological similarity. Results suggest that in all three countries, shared group membership plays an important role in shaping second-order political beliefs, though the effect of socio?demographic similarity is only robust in the absence of a clear partisan affiliation.© Informa UK Limited, Taylor & Francis Group, CC BY-NC-ND