Annals of Statistics
- Ann. Statist.
- Volume 30, Number 5 (2002), 1412-1440.
Parameter priors for directed acyclic graphical models and the characterization of several probability distributions
Dan Geiger and David Heckerman
Abstract
We develop simple methods for constructing parameter priors for model choice among directed acyclic graphical (DAG) models. In particular, we introduce several assumptions that permit the construction of parameter priors for a large number of DAG models from a small set of assessments. We then present a method for directly computing the marginal likelihood of every DAG model given a random sample with no missing observations. We apply this methodology to Gaussian DAG models which consist of a recursive set of linear regression models. We show that the only parameter prior for complete Gaussian DAG models that satisfies our assumptions is the normal-Wishart distribution. Our analysis is based on the following new characterization of the Wishart distribution: let $W$ be an $n \times n$, $n \ge 3$, positive definite symmetric matrix of random variables and $f(W)$ be a pdf of $W$. Then, $f(W)$ is a Wishart distribution if and only if $W_{11} - W_{12} W_{22}^{-1} W'_{12}$ is independent of $\{W_{12},W_{22}\}$ for every block partitioning $W_{11},W_{12}, W'_{12}, W_{22}$ of $W$. Similar characterizations of the normal and normal-Wishart distributions are provided as well.
Article information
Source
Ann. Statist., Volume 30, Number 5 (2002), 1412-1440.
Dates
First available in Project Euclid: 28 October 2002
Permanent link to this document
https://projecteuclid.org/euclid.aos/1035844981
Digital Object Identifier
doi:10.1214/aos/1035844981
Mathematical Reviews number (MathSciNet)
MR1936324
Zentralblatt MATH identifier
1016.62064
Subjects
Primary: 62E10: Characterization and structure theory 60E05: Distributions: general theory
Secondary: 62A15 62C10: Bayesian problems; characterization of Bayes procedures 39B99: None of the above, but in this section
Keywords
Bayesian network directed acyclic graphical model Dirichlet distribution Gaussian DAG model learning linear regression model normal distribution Wishart distribution
Citation
Geiger, Dan; Heckerman, David. Parameter priors for directed acyclic graphical models and the characterization of several probability distributions. Ann. Statist. 30 (2002), no. 5, 1412--1440. doi:10.1214/aos/1035844981. https://projecteuclid.org/euclid.aos/1035844981

