This post originally appeared on Sciblogs.co.nz.

Whilst filming an episode of Media 7 on Wednesday about the CSI effect, I was struck (not physically) by two things:

1. people genuinely seem interested in the CSI effect;

2. everyone has a different take on what it is and how they see it in the programmes they watch.

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It was interesting to hear Marie Dyhrberg, a prominent Auckland defence barrister, talk about how less time now has to be spent by expert witnesses explaining concepts like DNA because juries already have some knowledge of them from watching TV crime fiction programmes.

That is supported by my own experience of explaining concepts to juries where the nods of the heads of understanding come quite quickly into the initial explanation. The exceptions are usually the subjects that don't make it into

CSI: Miami

or

Bones

.

The area in which I have encountered the most problems is alcohol consumption. Explaining the difference between absorption and elimination is not glam and doesn't translate into a gory re-enactment of the scene beyond some swigging of lager and a bit of staggering by the actor.

A good understanding of forensic science must also help an investigative journalist like Donna Chisholm, who was involved with the David Dougherty case. Writing a story that contains technical scientific information for a general interest publication must be easier if your readership already has an understanding and an interest in the world of forensic science. It won't be helped of course by the leaps of interpretation that are made on TV programmes, like those in last night's episode of Bones.

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I can't go into detail because I shouted over it but it went something along the lines of: "Look at this previously unnoticed crack in the bone that I am suddenly and spontaneously examining with a look of revelation and excitement on my face. Without turning over the bones or examining the interior of the damaged surfaces I know that this must have been caused six months prior to the death of the victim and she was stabbed in the arm with a knife used to cut cacao plants."

Then there was the incredible situation where one of the scientists managed to insert large needles into a giant bar of chocolate and draw out the gases from two bubbles that they had managed to visualise on a computer screen (on the first go - they didn't spend five minutes stabbing around in the not-even-a-little-bit-melting chocolate: oh yes, that was because they turned the air con down in the lab...) Not only could they say that one of the bubbles contained blood from the killer that the victim exhaled during her last breath after she had somehow managed to get the killer's blood in her mouth but they were also able to say that the other bubble contained air from a burp caused by a specific brand of champagne. Now, I am more than happy to be corrected if I'm wrong but that really does seem to stretch the bounds of the credible.

Many people are apologetic about watching these sorts of crime programmes, which suggests that they know they're not realistic - and that should be of some comfort to the people who think that the CSI Effect generally has a negative impact on the general public's understanding of forensic science.

I do think that a greater awareness of forensic science and, importantly, its limitations, has to be good for the justice system. Without wanting to sound repetitive (but I am) forensic science needs to be transparent so that all parties can be assured that the science is being fully, fairly and accurately reported. With juries expecting science to have a place in criminal casework, I would also hope that they think about what is being presented to them.

The next question is, do juries make judgements of expert witness evidence (who to believe, basically) based on what the jury knows from the TV or based on what the expert witnesses say in court or both?

And why is there only ever one, unchallenged interpretation of the set of scientific results presented in

Bones

?!

Dr Anna Sandiford is a forensic science consultant and expert witness. View her work and that of 35 other scientists and science writers at Sciblogs, New Zealand's largest science blogging network.