"Lawyers in the United States have been known to use the following reason for striking down potential jurors: the prospective juror is well educated in science, or has some knowledge of genetics or probability theory." - Richard Dawkins Unweaving the Rainbow

Interestingly, this quote comes from the same year (2000) as the debut of forensic procedural television show CSI: Crime Scene Investigation, and is one of the earliest I've found to (popularly) call attention to the idea that the outcome of criminal cases should be becoming more contingent upon the ability of all involved (police, jurors, lawyers, technicians, judges, experts, etc.) to correctly interpret and understand scientific evidence, but perhaps are not.

It's been reported by some that the immense popularity of American television shows such as CSI: Crime Scene Investigation are having an apparent impact on the verdicts juries render by causing them to demand more television-style forensic proof, while contributing to a general misunderstanding of the real-life forensic investigative processes in use today. However, the demonstrable effects of such a phenomenon, if it exists, seem to be unclear.

"programs also foster what analysts say is the mistaken notion that criminal science is fast and infallible and always gets its man. That's affecting the way lawyers prepare their cases, as well as the expectations that police and the public place on real crime labs. Real crime-scene investigators say that because of the programs, people often have unrealistic ideas of what criminal science can deliver". source There is disagreement as to whether or not the effect is real and demonstrable, but there is also some debate as to which side is affected more:

Many lawyers, judges and legal consultants say they appreciate how CSI-type shows have increased interest in forensic evidence.

"Talking about science in the courtroom used to be like talking about geometry — a real jury turnoff," says Hirschhorn, of Lewisville, Texas. "Now that there's this almost obsession with the (TV) shows, you can talk to jurors about (scientific evidence) and just see from the looks on their faces that they find it fascinating."

But some defense lawyers say CSI and similar shows make jurors rely too heavily on scientific findings and unwilling to accept that those findings can be compromised by human or technical errors.

Prosecutors also have complaints: They say the shows can make it more difficult for them to win convictions in the large majority of cases in which scientific evidence is irrelevant or absent. source

  • Has it been proven that television shows such as CSI are affecting verdicts by influencing the way jurors interpret evidence (or lack thereof) presented in court?
  • If so, has it been shown to work in favor of either the prosecution or the defense?

1 Answer 1


From the Yale Law Journal (2006):

As chief prosecutor for Maricopa County, which includes the city of Phoenix, my office prosecutes about 40,000 felonies each year and includes a staff of 300 prosecutors.

In June 2005, we surveyed 102 of those attorneys, all of whom had trial experience, and they reported that the CSI effect is no myth:

Of the prosecutors we surveyed,

  • 38% believed they had at least one trial that resulted in either
    an acquittal or hung jury because forensic evidence was not available, even though prosecutors believed the existing testimony was sufficient by itself to sustain a conviction.
  • In about 40% of these prosecutors’ cases, jurors have asked questions about evidence like “mitochondrial DNA,” “latent prints,” “trace evidence,” or “ballistics”—even when these terms were not used at trial.


What may be of greatest concern is what goes on in the jury room, after arguments have been made. In 72% of cases, prosecutors suspect that jurors who watch shows like CSI claim a level of expertise during jury deliberations that sways other jurors who do not watch those shows.

Although verdicts have not yet noticeably changed from guilty to not guilty, prosecutors have had to take more and more preemptive steps to divert juries from reliance on television-style expectations.

From The Economist (2010):

In 2008 Monica Robbers, an American criminologist, defined [the CSI effect] as “the phenomenon in which jurors hold unrealistic expectations of forensic evidence and investigation techniques, and have an increased interest in the discipline of forensic science.”

Now another American researcher has demonstrated that the “CSI effect” is indeed real.

Evan Durnal of the University of Central Missouri’s Criminal Justice Department has collected evidence from a number of studies to show that exposure to television drama series that focus on forensic science has altered the American legal system in complex and far-reaching ways.

His conclusions have just been published in Forensic Science International.

The most obvious symptom of the CSI effect is that jurors think they have a thorough understanding of science they have seen presented on television, when they do not.

According to Mr Durnal, prosecutors in the United States are now spending much more time explaining to juries why certain kinds of evidence are not relevant.

Examples (via ForensicScience.net):

  • In State v. James Calloway, officers from the Arizona Department of Corrections discovered a syringe in a cell with a note attached to it, signed “Jimbo”—an inmate who just so happened to have a fresh mark on his arm consistent with syringe use. Jimbo even admitted that the syringe was his.
    However, the jury in this case criticized the prosecution because no DNA or fingerprint analysis was done on the syringe, and they demanded a handwriting comparison.

  • In State v. Everett Black, the defendant was caught carrying drugs in a cigarette pack. The defendant admitted that it was his pack, but he denied owning the drugs.
    At trial, the jury's foreman said that, based on what he had seen on “CSI”, the investigators should have done extensive fingerprinting, DNA testing, and other forensic procedures. This foreman convinced the entire panel that the police had not done their job well enough.

  • In 2004, a gang member in Peoria, Ill., stood trial for raping a teenager in a local park. The case looked like a slam-dunk. The saliva on the victim's breast matched the defendant's saliva, and there was plenty of compelling testimony from the victim and responding officers.
    However, the jury found the defendant not guilty. They felt that the “debris” found on the victim should have been tested to see if it matched the park's soil. According to the
    prosecutor, the jury claimed “they knew from ‘CSI' that police could test for that sort of thing.”

Ohio Takes Action Against the “CSI Effect” on Juries (2010):

The Ohio State Bar Association this week addressed the issue head on, creating jury instructions that explicitly warn about the influence of CSI and other TV legal dramas, including Boston Legal and Judge Judy.

... there are many reasons why you cannot rely on TV legal programs, including the fact that these shows: (1) are not subject to the rules of evidence and legal safeguards that apply in this courtroom, and (2) are works of fiction that present unrealistic situations for dramatic effect.

While entertaining, TV legal dramas condense, distort, or even ignore many procedures that take place in real cases and real courtrooms. No matter how convincing they try to be, these shows simply cannot depict the reality of an actual trial or investigation. You must put aside anything you think you know about the legal system that you saw on TV.


  • “acquittal or hung jury because forensic evidence was not available, even though prosecutors believed the existing testimony was sufficient by itself to sustain a conviction” – well, that sounds like an extremely positive development to me. Seems like CSI does some good after all. Jul 18, 2011 at 12:06
  • similarly in the Netherlands, the national forensics lab (we only have 1 for the entire country) experienced a dramatic increase in requests for their services from police agencies after CSI and similar shows started airing, often the type of tests asked for being similar to what was used on the shows aired last.
    – jwenting
    Jul 19, 2011 at 7:21
  • 2
    They let a rapist go free because the police didn't test the soil on her clothes?? That really boils my piss.
    – MSpeed
    Jul 21, 2011 at 14:32

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