The CSI Effect

Donald E. Shelton, Eastern Michigan University, has published "The 'CSI Effect': Does it Really Exist?" in volume 259 of the National Institute of Justice Journal (2008). Here is the abstract.

Many attorneys, judges, and journalists have claimed that watching television programs like CSI has caused jurors to wrongfully acquit guilty defendants when no scientific evidence has been presented. This so-called effect was promptly dubbed the "CSI effect," laying much of the blame on the popular television series and its progeny. This study of 1027 jurors found that 46 percent expected to see some kind of scientific evidence in every criminal case; 22 percent expected to see DNA evidence in every criminal case; 36 percent expected to see fingerprint evidence in every criminal case; and 32 percent expected to see ballistic or other firearms laboratory evidence in every criminal case. The findings also suggested that expectations for particular types of scientific evidence seemed to be rational based on the type of case.

For all categories of evidence CSI viewers generally had higher expectations than non-CSI viewers but the CSI viewers had higher expectations about scientific evidence that was more likely to be relevant. Interestingly, potential jurors' increased expectations of scientific evidence did not translate into a demand for this type of evidence as a prerequisite for finding someone guilty. Jurors were more likely to find a defendant guilty than not guilty even without scientific evidence if the victim or other witnesses testified, except in the case of rape. On the other hand, if the prosecutor relied on circumstantial evidence, the prospective jurors said they would demand some kind of scientific evidence before they would return a guilty verdict.

There was scant evidence in our survey results that CSI viewers were either more or less likely to acquit defendants without scientific evidence. Only 4 of 13 scenarios showed significant differences between viewers and non-viewers on this issue, and they were inconsistent. In the "every crime" scenario, CSI viewers were more likely to convict without scientific evidence if eyewitness testimony was available. In rape cases, CSI viewers were less likely to convict if DNA evidence was not presented.

In both the breaking-and-entering and theft scenarios, CSI viewers were more likely to convict if there was victim or other testimony, but no fingerprint evidence. Although CSI viewers had higher expectations for scientific evidence than non-CSI viewers, these expectations had little, if any, bearing on the respondents' propensity to convict.

Download the article from SSRN here.

Other scholars and commentators have written about the "CSI Effect." Here are some citations.

Stefan Lovgren, CSI Effect Is Mixed Blessing
Kit D. Roane, The CSI Effect
Jeffrey Toobin, The CSI Effect