Fingerprints are far from the slam-dunk form of identification that pop culture represents them as. There are tons of worrying cases of mistaken identity caused by faulty fingerprinting, in which even the justice system has to admit that the suspects are probably not Keyser Soze-ing their way to freedom. While prints are unique and pretty easy to match when you have two perfect samples to compare, that is almost never the case.
In the real world, cops are usually trying to match a partial print, which may be smudged, distorted, and/or fossilized in a mess of blood and clown makeup. We all know a crime scene is not exactly an optimal workplace condition, and some errors are to be expected. But that makes it all the more concerning that even in accuracy tests with complete prints and ideal conditions, the error rate is still anything between 3 and 20 percent.
Though the computers are still a vast improvement over the older method of eyeballing it.
However, because fingerprints are ideally reliable and have been used with success for years, they continue to carry a lot of weight in courtrooms. Even if the experts know the system has flaws, that's not what's ingrained in the minds of the jury. A fingerprint match has to equate to guilt; the alternative is that Law & Order lied to us, and we simply can't take that kind of hurt from you, Detective Stabler. Not from you. So when an expert goes in front of the jury and says they have a match, it doesn't really matter how many "howevers" and "partials" and "inconclusives" they bandy about. The jury heard that the prints match, saw the stern but paternal glare of Christopher Meloni in their mind's eye, and came back with a guilty verdict.
Some have tried to fix the system, or implement new measures, but there's one problem with that: If a judge decides that fingerprints cannot be used to convict, it will leave every single conviction based on fingerprint evidence open to reinterpretation. Thousands of convicts -- many of whom are likely guilty, hardened criminals, and the rest of whom are probably justifiably pissed off about their false convictions and have had a lot of time to work out lately -- would flood the streets, and society at large would devolve into Purge-style mayhem.
"Wait, was that not our endgame the whole time?"
And that is not a movie we'd like to live in. Maybe if it was Road Warrior, we could be convinced, but gas prices are way too high for that to be an economically viable apocalypse these days.
#1. The PCL-R
The Psychopathy Checklist-Revised determines what kind of punishment a person gets after they're convicted of a crime, whether that person is granted parole, and even whether they should be executed. But at its core, it's something simpler: a test for determining if you're a psychopath.
"Now, I'm just going to leave the room for a minute ..."
The idea is to measure the levels of 20 different "psychopathic" personality traits (such as glibness, promiscuity, superficial charm, callousness, and need for stimulation) in a subject by asking them questions and rating the answers. If that sounds a bit more terrifyingly vague than you'd like the "should you die" test to be, well, you're not alone.
The PCL-R can be skewed by a whole host of factors, all revolving around the score keeper: how they feel about the subject, how good they are at administering the test, how they are feeling that day, pretty much anything. If you show up for the test wearing your Team Edward shirt, and the tester is rooting for Team Jacob, there's a decent chance your results are going to be somewhere in the range of "irredeemable maniac that we must expel from the face of the Earth."
"I'm going to recommend death by exsanguination. Yeah, not so romantic now, is it?"
But hell, this doesn't apply to you; you're not in jail. Mostly because nobody's actually caught you committing any of your many, many terrible crimes. You get a pass on the psycho test, right? Nope! The PCL-R can be used to detain people who score high enough, even if they haven't committed any crimes yet. Use of the test isn't confined to those "let's stone people to death for eating birds on 'don't eat birds' day" legal systems, either -- right now it's employed in places like Canada, Australia, and (of course) the United States.
Maybe this still doesn't concern you. Maybe you're confident that you can pass this test, no matter how unintentionally skewed the results may be. What about the times the results are intentionally skewed? One study found that testers acting on the behalf of legal prosecution routinely give higher psychopathy scores to subjects than the ones working for the defense.
"Yes, I understand your test says she's Mother Theresa, but that still doesn't explain how the bunny got into the damn pot."
Do try to calm down: Raving fearfully about the conspiratorial psycho-test is an automatic failure of the psycho-test.
Sara Ohlms spends her time playing with her dog and tweeting jokes that sounded a lot funnier in her head.
Related Reading: There are a few tests our species could really use. The Cracked forums put a few suggestions together. If you're curious about the wide and exciting world of life as a human test subject, Cracked can help too. For a look at more of the bullshit people believe about psychology, click here.