With their ability to balance measured and unmeasured confounders, randomized controlled trials (RCTs) provide the highest level of evidence regarding the effect of treatment. Analyses of administrative data have had inconsistent success when compared with the results of RCTs. Much of the error can be attributed to the quality and completeness of the data sources as well as suboptimal study design and analytical approaches which differ significantly from the RCT. The comprehensive, longitudinal data within Electronic Health Records (EHRs) can overcome the data quality issues. This report describes a new analytical method for EHR data that successfully replicates RCT results.