Psychic detective

Psychic detectives are just regular old psychics with an added quirk — that of seeing themselves as courageous miracle-workers, applying their special powers in order to fight solve crimes and save the day! A bit like superheroes, sans the spandex (in some cases).

This is all absolutely fantastic, except for one little snag: there's never been a single documented crime case that was unequivocally solved by a psychic detective. And despite the title, they are rarely — if ever — actually trained as detectives.

Conversely, however, every single time a psychic has been consulted by investigators, valuable time and resources have invariably been wasted in doing so, never mind the asshole psychic occasionally managing to send the whole investigation on a wild goose chase. All the more ethical, considering how often psychics solicit their "services" to the grieving parents of lost or abducted children.

By the powers of Grayskull
Psychic predictions fall into three categories:
 * 1) Specific claims ("the body is buried near that specific tree"), which always turn out to be false;
 * 2) Vague and broad claims ("the body is near water"), which are bound to be true some of the time;
 * 3) Claiming you knew it all along after the fact ("I was told the body was buried there last night").

The lack of success is not for lack of trying, as psychics volunteer their services frequently to the police, especially in missing persons cases and other high-profile cases. Some police departments even feel obliged to warn families about such people: "however desperate you become, do not resort to the psychics and mystics who invariably approach parents in this situation. Such people will charge you large amounts of money but do not help you."

Examples of successes
So far there are no documented cases beyond the occasional anecdote. If you know one, contact the JREF and receive your million dollars!

It is important to realize that a few psychic detectives appearing to have predicted something is not good proof of anything. There are a large number of predictions being made, and some — even some very improbable ones — will turn out to be true by chance. If there's a 1-in-1,000 chance of something happening, it's very likely to happen if you try 5,000 times. This is the Law of Large Numbers.

Another potential pitfall is the Texas sharpshooter fallacy; like the Texan drawing the bullseye on the hole, due to confirmation bias, people tend to look for evidence that may confirm whatever the prediction was, and due to selective reporting, people tend to fail to notice anything that isn't unusual (like a random guess turning out to be wrong). For example, a psychic may say "the body is near the water", but what exactly does that mean? A river? A lake? The ocean? A bottle of water? What is "near"? In your pocket? Across the street? In the same city?

A number of controlled double-blind tests have been conducted, in which experimenters presented would-be psychics with photos of or evidence from actual crime scenes, asking them to describe the crimes which had taken place. So far, no psychic detective has done better than chance. Surveys among police departments also haven't yielded any positive results.

Claimed successes that aren't

 * Ben Radford of the Committee for Skeptical Inquiry challenged pseudosceptical investigator Alex Tsakiris to "find the best case you can find. Look through all the psychics you want, figure out one, and pick the one case you think is airtight". Tsakiris chose the case of Nancy Weber, who claimed to have helped apprehend the serial killer James Koedatich in 1983. Radford spent some time investigating the case, going so far as to interview some of the detectives who worked on the case, and found there are conflicting accounts and no hard proof of any special powers.

Examples of spectacular failures

 * Sylvia Browne did many psychic feats, and being a psychic detective was one of them. She claimed to have an accuracy rate of "somewhere between 87 and 90 percent". The Committee for Skeptical Inquiry found 115 cases, and found that 25 were flat-out wrong, and the other 90 were unconfirmable due to lack of details or the crime not being solved yet. Browne was wrong spectacularly in some cases; telling families that their missing children were alive or dead, which later turned out to be false. Some notable whoppers include, but are not limited to:
 * In 1999 she told Opal Jo Jennings' grandmother that Jennings was still alive and in Japan. Her body was found in 2003 and found to have been killed almost immediately after being kidnapped.
 * In 2002, Browne told Holly Krewson's mother that Holly is addicted to drugs and in Los Angeles working as an erotic dancer. Her family made trips to LA and frequented nightclubs looking for her. In 2006 it was discovered that unidentified remains found in 1996 were Holly's.
 * She informed the mother of Amanda Berry that her missing daughter was dead. As it turns out, Berry was very much alive. Oops.
 * A group of psychics told Dyfed–Powys Police (Wales) that they had been in touch with the ghost of a suicide victim. At the urging of the friends and family, the police investigated this. Result: all specific claims turned out to be false. Damage: five wasted months, a useless second post-mortem, and at least £20,000. To quote an involved police official: "We are in danger of becoming a laughing stock. We went haring across the country based on info from cranks".
 * The spawned many tips from psychics; none of the tips panned out, and many were completely off the mark.

"But what's the harm?"
You mean, aside from the emotional damage and false hope (depending on what nonsense the psychic PIDOOMA'ed) to family members of missing people?

Many police departments make efforts to follow up on all leads, the success of this depending on the sanity of whoever is in charge and how much the family pushes for "help" from psychics. One can hardly blame the family; most people will grasp any straw — no matter how small — when their child is missing, and that's entirely understandable. As a result, though, they are ruthlessly exploited by the so-called psychics (read: charlatans) who take advantage of their plight.