The value, of course, is that they provide us with more objective views than eyewitness testimony, for example. There’s a bit of a forensics craze running the country with shows like CSI making the idea of forensic evidence popular and fun.
But such shows tend to distort the picture in various ways. To make an hour’s show, tests must come back more quickly than they would in real life. Again, in real life there would be many more frustrations on a daily basis, and equivocal evidence would be much more common.
Radley Balko has a story about manufactured evidence (HT: his Agitator blog), and a particularly blatant one. His story comes as the National Academy of Science has released a report (link to press release, report is linked from release on problems with various types of forensic evidence as used in our court system.
The danger of forensic evidence? It is studied and presented by people, and sometimes people are incompetent or dishonest. The NAS report suggests a number of necessary remedies.
I would hope that this would not discredit the ideas involved in the mind of the public. Rather, I would hope we would be prepared to support those who do their jobs well, but hold accountable those who don’t.