The CSI Effect: 6 Reasons Why TV Crime Shows are Patently Absurd

So, you think you can be a one-person, crime-fighting, uniformed crusader do you? Single-handedly blowing the case wide open and putting those cops that initially attended the scene to shame? Not so fast. While forensic investigation can certainly make or break the case, all the Grissoms in the world couldn’t handle a single murder on their own. The truth is a serious offence is often the subject of a long, complex investigation which requires the cops, forensic experts and intelligence management to be a success.

In a standard, high profile investigation, an SIO (Senior Investigating Officer) is appointed by the police. They will almost certainly be a detective, and usually a Sergeant or higher. Their job is to take an overview of the case and delegate the actions that officers and forensics experts will be conducting. This is going to be a harsh reality check for you, Horatio. Think you can get your DNA “fast tracked” through the lab and back in fifteen minutes? Think again.

There’s plenty of difference between TV crime shows and real life, and we’re going to show you which ones we think are the most absurd (we’ve also taken the initiative to tell you even more about this here).


1. “Enhance.”

This refers to the seemingly endless ability of TV forensics to take the blurriest piece of CCTV and expand it to reveal licence plates, written data, or the reflection of a killer in a shop window holding a smoking gun (!). This just can’t happen in real life. Whilst there is a facility to enhance an image within police imaging units, this function is very limited and cannot exceed the capability of the camera that captured the image in the first place. What we’re saying here is if your camera is a 340×480 VGA, no amount of post-processing is going to make the already captured data any clearer.


2. “High Level Science, Low Level Crime.”

What we’re talking about here is the increasing tendency of juries to expect detailed forensic analysis for basic offences. Let’s take the case of a minor assault — where the suspect is known to the victim. Ordinarily, no forensic analysis will be done here as it’s unnecessary and too costly. Still, a recent NPR study has shown that more American jurors are expecting precisely this sort of thing in minor cases, where previously it wouldn’t have even been considered. Another 2008 study showed that 69 percent of judges thought that the jurors had unrealistic expectations of forensic evidence.  In the era of cutbacks we’re living in, as a forensic scientist, don’t expect to be assigned to everything that comes through the door.


3. Unnecessary science.

TV makes us think that every possible line of analysis ought to be followed; in actual fact, it’s often unnecessary. A recent example was a homicide trial in which the defendant’s bloody coat had been found at the crime scene. The defendant had admitted his presence at the scene. The jury asked the judge why a DNA comparison test had not been carried out, even though it wasn’t relevant – the DNA would have done nothing more than confirmed the defendant’s presence, a fact which he already admitted. Such an examination would be pretty expensive too.


4. Science is certain.

Few things in life are, and DNA in blood is a prime example of this. According to recent police reports, there is roughly a 1:1 billion chance of your blood DNA profile matching someone else’s. For trace DNA recovered at a scene, the chance of it being similar increases. Although a compelling case could be made that blood found at a crime scene with a similar profile to your own is indeed yours, nothing can be taken with certainty. Forensics works on probability — but the TV doesn’t always show this.


5. Fingerprints are everywhere.

In almost every CSI episode, some compelling fingerprint evidence is found on something, and matched to a felon using sophisticated computer comparison almost instantly. Whilst fingerprint searching is much faster in real life now (taking hours instead of days), its never as fast as depicted on a TV show. Furthermore, almost all criminals are aware of the potential for fingerprint evidence and even in the most rudimentary of crimes will wear at least wooly gloves, which virtually prevents finger marks being lifted from crime scenes. In real life, relatively few fingerprints are recovered from scenes.


6. CSI back fire.

It may shock you to learn that criminals watch TV too, and will take every opportunity to destroy evidence that may lead back to them. For them, CSI is a veritable fountain of inspiration. From the wearing of surgical caps (to prevent hairs being left) to the usage of DNA-destroying bleach at a crime scene, criminals exploit the increased awareness of forensics to their own advantage – in effect, putting us on the back foot. Thanks a lot, TV!


Your Turn: We’ve actually got a few more of these up our sleeves for a later post. Let us know if you’ve got anything to add in the comments (maybe we’ll feature it in the next instalment). We’d love to hear from you.



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