The Expert Working Group on Human Factors in Forensic DNA Interpretation has conducted a scientific assessment of the effects of human factors in forensic DNA analysis. The Working Group evaluated relevant bodies of scientific literature and technical knowledge to develop recommendations to improve practice and reduce the likelihood of errors. This report provides a comprehensive discussion of human factors as they relate to all aspects of DNA analysis, from interpreting electropherograms to reporting results and testifying in court. This expert working group is supported by the National Institute of Justice (NIJ) Office of Investigative and Forensic Sciences (OIFS) and the National Institute of Standards and Technology (NIST) Special Programs Office.