 Many stories about the CSI effect assume that there has been an increase in acquittal rates, though this is often based entirely on anecdotal evidence. A 2009 study of conviction statistics in eight states found that, contrary to the opinions of criminal prosecutors, the acquittal rate has decreased in the years since the debut of CSI. The outcome of any given trial is much more strongly dependent on the state in which it took place, rather than whether it occurred before or after the CSI premiere. A 2010 study by the University of Wisconsin – Milwaukee suggests that, while there may be a correlation between crime show viewership and a perceived understanding of DNA evidence, there was no evidence that such viewership affected jury decision making. As of August 2010, no empirical evidence has demonstrated a correlation between CSI viewership and acquittal rates. One researcher suggested that the perception of a CSI effect — and of other courtroom effects, such as Perry Mason syndrome and white coat syndrome — is caused not by the incompetence of jury members, but by a general distrust of the jury system as a whole.
