We present a novel hierarchical prior structure for supervised transfer learning in named entity recognition, motivated by the common structure of feature spaces for this task across natural language data sets. The problem of transfer learning, where information gained in one learning task is used to improve performance in another related task, is an important new area of research. In the subproblem of domain adaptation, a model trained over a source domain is generalized to perform well on a related target domain, where the two domains’ data are distributed similarly, but not identically. .