Population health relies on tracking patients through a continuum of care with patient records from disparate sources. An assumption is made that all patient records are connected. The reality is: they are not. Disconnected records negatively impact results: from individual patient care management through population health''s predictive analytics. An enterprise master patient index (EMPI) system can be employed to connect all patient records, but it requires comprehensive tuning to maximize the number of connected records. This presentation describes how one large healthcare integrated delivery network tuned their EMPI system to maximize the number of connected patient records across all sources.