Through CSI, jurors have been introduced to forensic sciences and testing techniques that are often innovative and on the cutting edge. However, many of the techniques displayed on the television show are unfeasible for local law enforcement agencies that are strapped for resources, or the techniques have not undergone proper testing for reliability. For instance, experts have doubts about the reliability of bitemark testing as a means of identifying suspects, but such techniques are used in the show. As a result, jurors will often over-estimate the reliability of forensic sciences and will also expect prosecutors to use forensic science testing in even simple and straightforward cases.

“Jurors know more about the types of testing that in theory, can be done, but they certainly don’t know when it’s appropriate to use those types of tests.”

http://nypost.com/2015/09/27/how-csi-twisted-our-jury-system/