How accurate are Polygraphs?

[D.johnson179]

I have known several people who have taken polygraph examinations. Some pass and some fail. However there are many who I know have lied and still passed. So how accurate is this exam?

[charlydevo]

The problem is that the results are interpretations of the polygrapher. They aren't admissible as evidence, but they can be used for pre-employment examinations. I don't think that they should be used at all, but I'm nobody important so it doesn't matter what I think.

[D.johnson179]

You are a cop though right?

[retdetsgt]

They're not fool proof, but are accurate enough for investigative purposes.

I've made a lot of criminal cases behind one. I'm not a fan of them for employment purposes either. Generally, you have to be a little sociopathic to lie and pass one.

[G35 Mass]

You are a cop though right?

You're not a detective though, right?

I am torn on them for employment purposes. Currently they're illegal for us in employment purposes (pre-employment or continuing employment).

After a spat of some very dirty cops in a very short time frame here in Mass recently, I can't help but wonder if a poly would help weed some of these guys out. On the other hand, I have to wonder if an examiner had misinterpreted my poly, where would I be today?

[txinvestigator1]

The problem is that the results are interpretations of the polygrapher. They aren't admissible as evidence, but they can be used for pre-employment examinations. I don't think that they should be used at all, but I'm nobody important so it doesn't matter what I think.

Polygraphs are admissable under certain conditions. I got schooled on that very fact right here on RP. lol

[mobrien316]

The research indicates that specific issue polygraphs can be highly accurate (dependent upon the skill of the examiner), while non-specific issue polygraphs (such as pre-employment exams) are little better than chance.

In a criminal investigation they can be quite useful, since they are essentially an interrogation designed to obtain the truth and obtain a confession. In that regard, with a skilled examiner, they are very accurate and very helpful.

For applicant screening, they are decidedly less accurate and, I believe, worse than worthless. The use of polygraph screening for law enforcement applicants carries with it the implication that people who "pass" are somehow more trustworthy, have fewer (or no) criminal incidents in their past, or have somehow been more thoroughly screened than people who fail. Such is simply not the case.

[retdetsgt]

After a spat of some very dirty cops in a very short time frame here in Mass recently, I can't help but wonder if a poly would help weed some of these guys out. On the other hand, I have to wonder if an examiner had misinterpreted my poly, where would I be today?

I tend to think that some agencies rely on them in order to make a less intensive BI. They're illegal for employment use here too and I'm fine with that. Besides, as I said, my experience has been that a sociopath can pass one easily because they have no conscience. In criminal cases, I've had several pass it in flying colors only to be convicted handily on real evidence. A few have failed it and I was able to clear them, but by in large it's usually accurate in criminal matters where we're looking at a specific event.

I think the feds have too much faith in it and tend to abuse it. The Army put my brother on one when he was a captain and the operator started a rambling interrogation like some sort of Nazi. My brother finally got pissed, tore off the leads and stormed out. A couple of months later, he was promoted to major so I guess it wasn't that important.

[Kimble]

However there are many who I know have lied and still passed.

You often hang out with liars?

[icu650]

I have an acquaintance that literally lies about everything, and he believes his own lies. If he worked at every occupation that he has said he did he would be 110 years old. My point is, I do believe that this idiot could pass the polygraph about any subject and walk out smiling.

[CPL1897]

Im not a fan of them iether, I know technology has changed since the 90's when I had my pre-employment for my agency but the examiner who I ended up working many cases with over the years prior to his retire told me and put "pen to paper" a "show of decite" even though I told the truth and was simply nervous about being strapped to a chair with wires and a scary man asking me questions when I was only 19....lol

[retdetsgt]

I don't think the technology of polygraphs have changed much at all since they went from vacuum tubes to solid state. They still read the same things and the operator makes assumptions as to what they mean. As I said, I like them for criminal investigations and have utilized them a few hundred times. But they are only one facet of case and should be used as such and never taken as the final word no matter what the outcome.

I think some people flunk just because they're nervous, but others because there may be something in their background they don't want to talk about and has nothing to do with what the operator is looking for. Like the open ended question about unreported crimes, a "crime" can be defined most anyway in someone's mind. That's like asking if you've ever lied, of course you have. Some people could flunk because they know they must have done something not disclosed, but can't recall everything and feel a twinge of guilt over that. Again, it depends too much on the ability of the operator to pre-question and interpret the results.

We have three polygraph operators and we didn't get to choose who ran the test for us. One guy was famous for "undetermined" and of the other two, one always found more people deceitful than the other did. That told me a lot about the reliability.

[ET109]

Should not be used for employment. The problem isn't that they're completely inaccurate- the problem is that people overstate their results. If it could be part of a broader picture and taken in context it might be useful, but too many people have a faith in the box for that to happen- if the polygrapher says you're lying, you're screwed.

And why not? They have two more applicants who might not be quite as good, but didn't come up as deceptive. That's why I think it has to be removed as a tool to use for backgrounds, it's too easy to rely on it.

[retdetsgt]

That's why I think it has to be removed as a tool to use for backgrounds, it's too easy to rely on it.

Yep, that's one of my points.

Years ago, I called a large, Southern police department to ask about them doing a courtesy polygraph on a homicide suspect that had moved down there. I tell you, it unnerved me more than a little bit that their polygraph operators were assigned to IA. You have to assume they are assigned to where they are called upon the most. I guess I've been spoiled because in Oregon, taking the polygraph cannot be a condition of employment, period.

[Kimble]

Years ago, I called a large, Southern police department to ask about them doing a courtesy polygraph on a homicide suspect that had moved down there. I tell you, it unnerved me more than a little bit that their polygraph operators were assigned to IA. You have to assume they are assigned to where they are called upon the most. I guess I've been spoiled because in Oregon, taking the polygraph cannot be a condition of employment, period.

If it was in AL (like Birmingham PD or Jefferson Co SO) it's not uncommon for IA in an agency to serve a dual purpose of "hiring and firing" (that is, they work as the recruitment/pre-employment division as well as working internal criminal/administrative investigations).