Title: bgms: Bayesian Analysis of Graphical Models of Binary and/or Ordinal Variables Author: Maarten Marsman Abstract: Multivariate analysis using graphical models is rapidly gaining ground in psychology. In particular, Markov Random Field (MRF) graphical models have become popular because their graph structure reflects the conditional associations between psychological variables. Although most psychological variables are assessed on an ordinal scale, the analysis of MRFs for ordinal variables has received little attention in the psychometric literature. In this talk, we propose an MRF for ordinal data to fill this gap and present a new methodology to test the structure of the proposed MRF. Testing the structure of an MRF requires us to determine the plausibility of the opposing hypotheses of conditional dependence and independence. To this end, we propose a Bayesian approach using the inclusion Bayes factor to quantify the (lack of) evidence for a given edge. The proposed methodology is implemented in the R package bgms. We will demonstrate the functionality of the bgms package for network analysis of binary and/or ordinal data and discuss current and future developments of the proposed model and methodology.