How Accurate are Police Sketch Artists?
Police sketches / composite profiles have always been a hallmark of good police investigation and sleuthing. And yet the composite drawings themselves have always been a subject of skepticism and doubt. And the doubters have some good points. Current stats indicate that on average, hand-drawn police sketches are only about 9 percent "accurate." "Accurate" in this case referring to the degree of recognizability that can be inferred from the perp based only on the composite drawing iteself. Even more surprising, computer generated composites (more on these later) are only about 5 percent accurate in helping to accurately identify suspects.
Why is accuracy such a problem?
Now I think we all agree, 9 percent doesn't sound good when you are trying to catch a thief or convicted felon. Are the sketch artists just not that good? Actually no, it's more like human memory / human recall is just naturally unreliable. Let's dig into the details.
In a very broad sense, we can classify human memory, our ability to recall facts and events, into two broad categories: Recall Memory and Recognition Memory. Recall Memory is memory that requires no priming. For example, when someone usually sees a picture of a chair, they can usually instantly recall that the name of that item is "chair." There is almost absolutely no downtime in making this kind of recall. Usually, this kind of memory is formed through an ennumerable amount of exposure with the subject of the recall.
On the flip side, Recognition Memory is memory that (surprise, surprise) requires priming to make strong associations and linkages in the brain. For example, you may see someone on the street who you do not instantly recognize but whose presence gives you the "feeling" that you know them or have known them before. After two hours have passed, you sit up and realize that "oh shit, I stood behind that guy at the DMV." Your brief interaction with that individual did not solidify your memory of them but their memory does exist in your mind to some level.
It is recognition memory that most police sketch artists have to deal with when questioning a victim or a witness. The interactions behind many crimes are so short that it should be no surprise that most people find it hard to recall facial features or details of the crime scene. When we look at things this way, it's actually really amazing that composite artists can reach a 9% accuracy. .......At least I think so. So let's see how these guys get their job done.
What is a police sketch artist's method?
Composite artistry is a honed skill-set like any other. There is no formal degree program for the profession, instead there are a combination of soft and hard skills that make for the ideal candidate. First of all, you need to know how to draw. Drawing and sculpture classes coupled with lots of practice should prepare you for the technical nature of the human face. From there you can duplicate facial features of work off of verbal descriptions.
It may also be helpful to have some psychology or communication skills under your belt as much of your work will involve trying to get someone to recall information from a brief (often traumatic) experience in their life.
Lastly, some police sketch artists found that volunteering with their local police force was a key factor in finally getting them some employment in the field.
Becoming a trusted and often utilized composite profiler is not just about how well you can draw. It is also about the process by which you obtained your composite image from someone else's mind. Police sketch artists have various methods for getting someone to recall the details of a person's face, but the general process is as follows:
1.) Sketch artist meets with the witness and calmly get the person to recall perps fiace without making victim relive traumatic events.
2.) Artist then set out to draw what witness describes, making sure to not only capture general facial features (i.e. large nose, narrow chin, tall forehead) but also to capture standout/ distinguishing features (i.e. tattoo, facial scars, bandanas). It is also at this point that artists may reference other visual aids such as a scrapbook of facial features that may help the witness to jog their memory.
3.) Lastly, either during the drawing process or towards the end; the witness is shown the composite drawing to get an agreement on the general appearance of the perp.
Do we still need Police Sketch Artists?
So now let's go back to our 9 percent issue. If police sketch artists are only able to get a 9 percent accurate description of a suspect, then how useful is that information in the real world. Might this kind of inaccuracy lead to false accusations, false leads, and more work for an overburdened police department. Possibly. However, some law enforcement officials say that there are some secondary reasons why police sketches may be helpful in a police investigation.
For instance, many correctly point out that while composite sketches don't necessarily serve to narrow down the suspect list to manageable level; in the absence of photographic or video evidence, they do help to increase general awareness about crimes. Even more importantly, composite sketches can get the general public on the lookout for suspicious persons and activities. Assuming the composite sketch looks even reasonably close to the criminal's face, this could put pressure on the perp or "tighten-the-noose" as they say.
A Note on Computer Generated Composites
As promised at the start of this hub I promised to include information on computer-generated composites. Well here we are. Computer-generated composites are the result of an algorithm that takes user (the witness) input (input usually in the form of whole-faces or facial features), and outputs a visually accurate composite sketch based on those inputs.
Of course we have already determined that computer-generated composite sketches generally suck (5% accuracy) compared to their human counterparts (9% accuracy). So why are we mentioning them? Well what you have to understand is that when police departments have to create composite sketches, today they are far more likely to use computer software rather than an actual in-person sketch artist. Why? Well it simply comes down to cost and availability.
Due to the ubiquity of camera and video technology in everyday life, the need for composite sketches has declined overall. The declining need for sketch artists has meant that less people are attracted to the profession in general, and those that are, often demand a significant hourly wage. Therefore, to avoid exorbitant costs for a service that is not in high demand, police departments will often turn to relatively low cost profiling software to get the job done.
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