Clarke EJREckerle FKerr JRHill SRLing MMarques MDWilliams MN2025-11-102025-11-102025-10-22Clarke EJR, Eckerle F, Kerr JR, Hill SR, Ling M, Marques MD, Williams MN. (2025). Extremism at the center: Uncovering political diversity among midpoint responders on the left–right self-placement item. Political Psychology. Early View. (pp. 1-21).0162-895Xhttps://mro.massey.ac.nz/handle/10179/73797The midpoint of the left-right self-placement item is hiding important political diversity, and may be conflating moderate responders with populists and other political sub-groups. Survey researchers should consider this problem when examining relationships between political orientation and political attitudes. We suggest testing for non-linearity in these relationships, and measuring anti-establishment and populist beliefs separately. Researchers interested in building theories explaining the psychological underpinnings of ideological extremism should also consider the possibility that a qualitatively different type of ideological extremist self-places on the midpoint.CC BY 4.0(c) 2025 The Author/shttps://creativecommons.org/licenses/by/4.0/Anti- establishment attitudesideology measurementleft–right self-placementpopulist attitudesscale midpointJournal article10.1111/pops.700821467-9221journal-article1-21