Learning Bayesian Networks from Incomplete Data with the Node-Average Likelihood

Abstract: Bayesian network (BN) structure learning from complete data has been extensively studied in the literature. However, fewer theoretical results are available for incomplete data, and most are related to the Expectation-Maximisation (EM) algorithm. Balov (2013) proposed an alternative approach called Node-Average Likelihood (NAL) that is competitive with EM but computationally more efficient; and he proved its consistency and model identifiability for discrete BNs. In this paper, we give general sufficient conditions for the consistency of NAL; and we prove consistency and identifiability for conditional Gaussian BNs, which include discrete and Gaussian BNs as special cases. Furthermore, we confirm our results and the results in Balov (2013) with an independent simulation study. Hence we show that NAL has a much wider applicability than originally implied in Balov (2013), and that it is competitive with EM for conditional Gaussian BNs as well.