The CSI Effect, Fact or Fiction?

The overwhelming popularity of crime and forensics TV shows like CSI, Law & Order and NCIS is having a profound impact on how our society views crime, but the storied effect of these shows on juries may be a myth.

A new study shows that watching these shows leads us to drastically overestimate the frequency of violent crime in our country.

The new research, from Purdue University, finds that frequent TV crime viewers estimated that the number of murders was 2-3 times higher than it is in reality. But true-crime junkies also think cops and lawyers are everywhere. They guessed that each group made up more than 16 percent of the American workforce. They're really less than one percent each.

So how does this altered perception of crime translate to the courtroom?

Prosecutors complain that these shows have raised juror expectations about forensic science, making them less likely to convict in cases without scientific proof (although only a small percentage of cases involve forensics). Defense attorneys worry about the flip side: that if prosecutors throw out any type of science or shiny pseudo-science, jurors will be star-struck by the CSI-like witnesses and will be more likely to convict. This is one reason we need forensic standards -- to ensure that nobody is being convicted based on untested brain waves or bootprints or voice stress analysis.

But are these worries based in reality? Maybe not. Two prominent studies focused on the prosecution's concerns found that while crime-drama viewers had different expectations and interpretations of evidence, they weren't more or less likely to convict base don forensics.

One 2006 study, from a judge and two Eastern Michigan University law professors, finds crime-drama viewers had a higher expectation for forensic evidence, but their votes to convict or acquit weren't affected. (Summary here, full study PDF here).

Another, from two Arizona State professors in 2007, found that CSI-lovers were more skeptical of questionable forensics and more confident of their verdicts, but once again, their verdicts weren't significantly different from jurors who didn't watch these shows.

There's more study to do, but in the meantime, it looks like the CSI Effect -- on juries at least -- may be more legend than fact. Whether our obsession with crime influences our political debate toward tough sentences, or whether it has us more worried about personal safety than we need be, those questions are still open.

Hat tip: Mike Smithhhhhhhh