Many senior U.S. law enforcement officials believe that the English criminal justice system has capitalized more fully on the crime-fighting potential of forensic DNA evidence than the U.S. criminal justice system. They contend that the English system is much faster at testing DNA samples and at uploading the test results into its forensic DNA database and that the English national DNA database provides more database hits that might help law enforcement solve and prevent crimes. Members of the RAND Center on Quality Policing (CQP) asked RAND researchers to explore the forensic DNA analysis systems in England and the United States to find out whether these perceptions are accurate. This report presents CQP's best efforts to undertake this comparative analysis, which was severely hampered by a lack of data on the U.S. and English forensic DNA systems and the unwillingness of some U.S. agencies to share their data. The authors make use of the limited available information to undertake comparisons of the two systems, highlighting the limitations of these comparisons. Additionally, they discuss broader issues that arose during the course of the analysis as to the appropriate metrics that should be used for comparison and the contextual factors that they think should be taken into account in any international comparison of DNA database systems.