Dr. Barr's research focuses on respiratory epidemiology with a focus on chronic obstructive pulmonary disease (COPD) and emphysema. In particular, he is interested in a better understanding of the causes of emphysema and COPD subtypes and uses machine learning to integrate advanced imaging (computed tomography [CT] and magnetic resonance imaging [MRI]) with multi-omic measures in large cohorts. He is principal investigator for the Multi-Ethnic Study of Atherosclerosis (MESA) Lung Study, the longest-running prospective study of emphysema on CT; the SPIROMICS Heart Failure Study, a large study of cardiopulmonary interactions using state-of-the-art echocardiography and MRI; a related study of deep-learning on CT scans; and the C4R CT Harmonization Study, which is harmonizing quantitative lung CT measures on CT scans from approximately 30,000 participants in 10 cohorts.