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Learning networks determined by the ratio of prior and data
Proceedings of the 26th Conference on Uncertainty in Artificial Intelligence, PMLR R8:605-612, 2010.
Abstract
Recent reports have described that the equiv- alent sample size (ESS) in a Dirichlet prior plays an important role in learning Bayesian networks. This paper provides an asymp- totic analysis of the marginal likelihood score for a Bayesian network. Results show that the ratio of the ESS and sample size deter- mine the penalty of adding arcs in learning Bayesian networks. The number of arcs in- creases monotonically as the ESS increases; the number of arcs monotonically decreases as the ESS decreases. Furthermore, the marginal likelihood score provides a unified expression of various score metrics by chang- ing prior knowledge.