"Multi-study factor analysis for biological data"

Il giorno giovedi 14 novembre la dott.ssa Roberta De Vito (Department of Biostatistics, Brown University) terrà un seminario presso l'aula XIV (palazzina ex Tumminelli), a partire dalle ore 12.00       We introduce a novel class of factor analysis methodologies for the joint analysis of multiple studies. The goal is to separately identify and estimate 1) common factors shared across multiple studies, and 2) study-specific factors.  We develop a fast Expectation Conditional-Maximization algorithm for parameter estimates and we provide a procedure for choosing the common and specific factors.   We present simulations evaluating the performance of the method and we illustrate it by applying it to gene expression data in ovarian cancer and to nutrient-based dietary patterns and the risk of head and neck cancer. In both cases, we clarify the benefits of a joint analysis compared to the standard factor analysis.   Moreover, we generalize the model in a Bayesian framework. We implement it using sparse modeling of high-dimensional factor loadings matrices, both common and specific, using the infinite gamma shrinkage prior. We propose a computationally efficient algorithm, based on a traditional Gibbs sampler, to produce the Bayes estimates of the parameters and to select the number of relevant common factors. We assess the operating characteristics of our method by means of simulation studies, and we present an application to the prediction of the biological signal from four gene expression studies on ovarian cancer.        
dott.ssa Roberta De Vito
14/11/2019 - 12:00
[aula XIV (palazzina ex Tumminelli) ore 12]