I suppose at some point we have all printed or aired them -- those police-generated composite sketches that could resemble darn near anybody they are so vague.
They are based on eye-witnesses who are often wrong to begin with. And still, we use the sketches because police say they help investigations.
Earlier this year,
The Times-Picayune in New Orleans
questioned whether police sketches are really all that useful. No doubt, sketches sometimes lead to arrests of the criminals at fault. But, as the
Times-Picayune found:
"The use and accuracy of such sketches, dating back many years, remains a hotly debated topic in the law enforcement community. Several studies have shown sketches are unreliable when it comes to identifying suspects, and many academics have decried their use. But most police departments, including New Orleans', still see them as a valuable tool."
The story continued:
"But when sketches are poor, the result can be trouble, said Tulane University criminologist Peter Scharf, a longtime critic of the NOPD. Inaccurate composite sketches can lead investigations astray, he said, causing tunnel vision among detectives and prompting citizens to look for a face that resembles the created portrait -- but not the criminal. The result, he said, could be the targeting of an innocent person.
"In a study completed last year, three university researchers showed nearly 400 college students 12 police sketches of suspects -- some computerized, some hand-drawn -- alongside a photograph of the suspect's face. They were asked if the two images depicted the same person.
"Overall, the students said 70 percent of the time that the sketches were not of the same person.
"American University professor John C. Watson, one of the researchers, called police sketches 'highly suspect.'
"The biggest x-factor in whether a sketch is going to be helpful or harmful is the reliability of the victim's memory, which is often difficult to gauge. Watson said witnesses are under stress during a crime, and emotion makes it hard to nail down important facial details."
Here is a similar story from the Pittsburgh Post-Gazette.
A piece presented at an annual ethics conference last year said police sketches are so unreliable that it may be unethical for the media to air or publish them [PDF] because of the damage they can cause to innocent people.
Here is a Web site that lets you create your own sketches and see how difficult it is to make a sketch look like a person you know.
