Andrew Bell is a Senior Lecturer (Associate Professor) at the Sheffield Methods Institute, University of Sheffield, UK. His current substantive research spans a diverse range of subject areas, including social epidemiology, geography, sociology, political science, public health, and economics. Methodologically, his interests are in the development and application of multilevel models, with work focusing on age-period-cohort analysis and fixed and random effects models. His twitter is @andrewjdbell.