All nodes with matching colors on the previous slide are connected to each other, and have matching sets of adjacent nodes In some sense, they contain 'redundant' information And in a measurement error setting, extremely highly correlated information If we know the strata, and we know the set of adjacent nodes for one member node, then we know the set of adjacent nodes for all other strata constituents For sampling purposes, it seems reasonable to represent these subpopulations by design
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