The UCSF Comparative Effectiveness Large Dataset Analytic Core (CELDAC) aims to enhance the capacity for analysis of large health datasets to conduct comparative effectiveness research. It provides support in study design, dataset acquisition, and methodological issues, while also making new Medicare public use files available for free to researchers. CELDAC's initiative is funded through an NCNNR grant, with a focus on enabling timely access to health data resources and fostering collaboration among researchers.