Can jury trial innovations improve juror understanding of DNA

A single spot of blood on a pink windowsill will tell investigators who broke a windowpane, turned a lock, and kidnapped 2-year-old Molly Evans from her bedroom in the middle of the night. An expert witness will testify that the DNA profile of the blood evidence recovered from the windowsill was entered into CODIS, an electronic database of DNA profiles. That process yielded a “hit,” identifying the defendant as the most likely source of the blood inside Molly’s room. But will jurors be able to understand the expert’s intricate analysis and use it to reach a verdict? And what—if any—steps can be taken to increase jurors’ comprehension of complex DNA evidence? Questions such as these prompted an NIJ-funded study on the impact of jury trial innovations upon mock jurors’ understanding of contested mitochondrial DNA (mtDNA) evidence. (See “How mitochondrial DNA compares to nuclear DNA, page 00.”) By examining how jurors in different experimental conditions performed on a Juror Comprehension Scale both before and after deliberations, researchers were able to assess whether four specific innovations improved jurors’ understanding of this complex evidence and identify which innovations worked best. Innovations tested The four innovations used in the experiment were: • Juror note taking. Mock jurors were given a steno pad and pen for note taking and were told that their notes would be available to them during deliberations. • Questions by jurors. Mock jurors could submit questions to the presiding judge, who obtained answers from an offsite DNA expert. • Mitochondrial DNA (mtDNA) checklists. This innovation guided jurors through complex mtDNA evidence by asking them a series of questions. (See “mtDNA evidence checklist, page 00.”) • Multipurpose juror notebooks. Mock jurors were given notebooks containing paper, copies of the two experts’ slides, the mtDNA checklist, a glossary of DNA terms used in the case, and a witness list.