The term was first reported in a 2004 USA Today article describing the effect being made on trial jurors by television programs featuring forensic science.
While this belief is widely held among American legal professionals, some studies have suggested that crime shows are unlikely to cause such an effect, although frequent CSI viewers may place a lower value on circumstantial evidence.
In each episode, the discovery of a human corpse leads to a criminal investigation by members of the team, who gather and analyze forensic evidence, question witnesses, and apprehend suspects.
In 2021, a new spinoff aired, CSI: Vegas, which brought back William Petersen and Jorja Fox, replaying their original roles as Gil Grissom and Sara Sidle, respectively.
In real investigations, DNA and fingerprint data are often unobtainable and, when they are available, can take several weeks or months to process, whereas television crime labs usually get results within hours.
[13] In addition to using unrealistic techniques, CSI ignores all elements of uncertainty present in real investigations, and instead portrays experimental results as absolute truth.
[14] The notion that these inaccurate portrayals could alter the public perception of forensic evidence was dubbed the "CSI effect", a term which began to appear in mainstream media as early as 2004.
[1][15][7] Under this effect, victims and their families – and jurors – are coming to expect instant answers from showcased techniques such as DNA analysis and fingerprinting, when actual forensic processing often takes days or weeks, with no guarantee of revealing a "smoking gun" for the prosecution's case.
[1] By 2009 more than 250 stories about the CSI effect had appeared in newspapers and magazines,[16] including articles in National Geographic,[15] Scientific American,[17][18] and U.S. News & World Report.
[19] Although the CSI effect is a recent phenomenon, it has long been recognized that media portrayals of the United States legal system are capable of significantly altering public awareness, knowledge, and opinions of it.
[6]: ch.4 News media reports on criminal trials, extensive internet blogging, and the successes of the Innocence Project have also contributed to the increased public awareness of forensic science.
[25] Donald E. Shelton, Young S. Kim and Gregg Barak have said it has changed the way many trials are presented today, in that prosecutors are pressured to deliver more forensic evidence in court.
Another study applied Gerbner's theory to a content analysis of popular crime dramas like CSI: Las Vegas, Law & Order: Special Victims Unit, Criminal Minds, and Without a Trace.
[37] In one highly publicized incident, Los Angeles County, California District Attorney Steve Cooley blamed actor Robert Blake's acquittal on murder charges on the CSI effect.
[43] In this case, the Maryland appellate court ruled the CSI effect voir dire question inappropriate due to its biased language and use of the term "convict" without mention of acquittal.
[45] In Goff v. State (2009), the prosecutor asked jurors during voir dire about their ability to render a verdict without scientific evidence, and then reminded them during closing arguments about this question.
[51] A 2008 survey by researcher Monica Robbers showed that roughly 80% of all American legal professionals believed they had had decisions affected by forensic television programs.
[54] One of the largest empirical studies of the CSI effect was undertaken in 2006 by Washtenaw County Circuit Court Judge Donald Shelton and two researchers from Eastern Michigan University.
[3] Shelton described one instance in which a jury member complained because the prosecution had not dusted the lawn for fingerprints,[56] a procedure which is impossible and had not been demonstrated on any crime show.
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.
A fan of CSI, McKinney went to unusual lengths to remove evidence of his crime: he cleaned his hands with bleach, burned the bodies and his clothing, and attempted to dispose of the murder weapon in a lake.
[71] Ray Peavy, head of the Los Angeles County homicide division, commented that, in addition to teaching criminals how to conceal evidence, crime shows may even "encourage them when they see how simple it is to get away with [it] on television".
Max Houck, director of the Forensic Science Initiative at West Virginia University, said although CSI may be educating criminals, people who resort to a life of crime generally are not very intelligent to begin with.
Larry Pozner, former president of the National Association of Criminal Defense Lawyers, argued that because people who commit violent crimes generally do not take precautions, television forensics programs are unlikely to have any effect on their behavior.
[74] New technologies and the increased public awareness of forensic science have stimulated new interest in solving cold cases and encouraged higher accountability among police investigators.