Tag Archives: CIS Effect

The CSI Effect

Via BoingBoing, The Economist investigates the “CSI Effect” – the phenomenon whereby facts, falsehoods and mythinformation about criminal forensics procedures in entertainment media is hampering (and sometimes aiding) the detection and prosecution of real criminals.

… a new phrase has entered the criminological lexicon: the “CSI effect” after shows such as “CSI: Crime Scene Investigation”. In 2008 Monica Robbers, an American criminologist, defined it 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.”


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. Mr Durnal cites one case of jurors in a murder trial who, having noticed that a bloody coat introduced as evidence had not been tested for DNA, brought this fact to the judge’s attention. Since the defendant had admitted being present at the murder scene, such tests would have thrown no light on the identity of the true culprit. The judge observed that, thanks to television, jurors knew what DNA tests could do, but not when it was appropriate to use them.

This sort of informational feedback loop happens in all sorts of places. I’m immediately reminded of the most common denigration of open-source software, namely that because anyone can download the code, anyone can work out how to compromise it. Of course, very few people do so… and proprietary software certainly isn’t immne from hacking, despite its closed nature. But is that because there’s less profit to be made from hacking Linux systems, as Microsoft advocates often suggest? Given the number of servers that run on *nix, I can’t believe it’s as clear-cut as all that.

But back to the forensics issue: the ‘open code’ of forensic science is helping some of the smarter criminals cover their tracks:

Criminals watch television too, and there is evidence they are also changing their behaviour. Most of the techniques used in crime shows are, after all, at least grounded in truth. Bleach, which destroys DNA, is now more likely to be used by murderers to cover their tracks. The wearing of gloves is more common, as is the taping shut—rather than the DNA-laden licking—of envelopes. Investigators comb crime scenes ever more finely for new kinds of evidence, which is creating problems with the tracking and storage of evidence, so that even as the criminals leave fewer traces of themselves behind, a backlog of cold-case evidence is building up.

Is there anything to be gained from trying to stem the flow of forensics knowledge out into the wider world? And if there is, how would one go about enforcing it?