This chapter examines distributions of variables and outcomes, conduct association analysis between them, and explores for temporal, spatial, or causal relations. It utilizes large amounts of administrative claims data, including various health care outcomes and thousands of variables, to complete descriptive analysis, and use various perspectives to examine the problem in-depth. The chapter also examines the utilization spectrum for emergency department visits and look for differentiating factors that contribute to utilization. It focuses on the temporal consistency of high utilizers’ visits to the emergency department. For total medical expenditure calculations, institutional and professional claims were included. Enrollee-level information included demographic variables, such as age at enrollment, sex, race/ethnicity, residential address, and residential county. Patients’ diagnostic history was based on International Classification of Diseases, Ninth Revision, Clinical Modification codes from all 25 available diagnosis fields from all available claims unless otherwise indicated.