This study tested whether the use of selected jury trial reforms enhanced jurors' understanding of complex and challenging scientific evidence presented during a criminal trial. The study examined the use of several jury reform techniques using a controlled mock jury approach in which mock juries composed of jury pool members watched a videotaped armed robbery trial featuring conflicting expert testimony about mitochondrial DNA (mtDNA) evidence. A total of 480 mock jurors were randomly assigned to eight-person juries and to one of the six conditions in the experiment. Ten mock juries were run in each of the six conditions (No Innovations, Note Taking, Question Asking and Note Taking, DNA Checklist and Note Taking, Jury Notebook and Note Taking, and All Innovations). At various points throughout the study (before the trial, after watching the videotaped trial, and after reaching a verdict), mock jurors were asked to complete questionnaires to gauge their understanding of mtDNA and the mtDNA evidence presented during the trial. They were also asked if and how the use of the jury trial innovations helped in their understanding of the mtDNA evidence. Specific variables contained in the study include demographic variables of the mock jurors, including their math and science background, mock jurors' views of science, their understanding of mtDNA, their perceptions of the reliability of different types of evidence, and the credibility of the prosecutor, defense attorney, detective, eyewitness, defendant, and expert witnesses, and whether the mock jurors favor or oppose the various innovations.