Fig. 2From: Assessing the causal relationship between income inequality and mortality and self-rated health: protocol for systematic review and meta-analysisDirected acyclic graph (DAG) illustrating cross-level confounding of an individual’s income on the relationship between income inequality and individual health, annotated with subscript t to account for time. Area-level variables (e.g. income inequality, X) are capitalized while individual-level variables are lower-cased (e.g. individual-level income i) [31]. Individual income should be conditioned upon (represented by the square around individual-level income) to remove the confounding effect of individual income on the relationship between income inequality and individual healthBack to article page