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by Peter Moskos

January 2, 2015

Stop lying! (and free Doug Williams)

"You're a fool if you go into a lie detector test thinking that telling the truth is good enough."

- Peter Moskos, John Jay College of Criminal Justice.
I've written about this before. Here I am saying much of the same... but this time it's on NPR.

What I find crazy is that the defenders of the test, the American Polygraph Association, is thrilled simply to find a study that says the test is "better than chance." Well, I should hope so!

But tell that to the 20 percent of applicants who get rejected while telling the truth.


Anonymous said...


What are your thoughts on the use of personality tests as a part of the psychological evaluation in the police recruiting process?

Here in Canada the MMPI-2 is often used. Are you familiar with this test? What type of psychological evaluation did you go through with BPD?

-From Canada

Peter Moskos said...

I know it. I took it (along with the polygraph). And I had an interview with "Dr. Outlaw"! How could I forget her name?

I think the MMPI is a horrible test for hiring because it's not designed to actually determine if you're crazy or not.

It was designed to help shrinks figure out what kind of personality disorder you might have if you have one.

That said, hell, if you can't pass it, maybe it is useful. But there are right and wrong answers for questions that people taking the test need to know. I like fire (bad answer). Some people may have good reasons not to love their parents (but it's not a good answer). Any why in the world is there a correct way to draw a house and tree?!

But I don't have a better answer.

Though maybe I do: one way to weed out bad cops is simply to ask officers, towards the end of training, if there is any officer in their class they would not want to work with, for whatever reason. If *half* the class puts down the same name, get rid of him or her.

I suspect it would be a good way to weed out the bottom 10% of the academy class, which is really not asking too much.

Somebody needs to bite the buck and get rid of a few bad cops before they have civil service protection and can't be fired.

But, at least in department I know, the hiring section wants to get a certain number through. Education and Training wants to get everybody through. Nobody wants to be sued for discrimination. As a result, there are some cops who simply aren't very good at the job.

campbell said...

Part of the MMPI thing is also to try and identify people with honesty problems, like answering yes to the "I always tell the truth" type questions. We did an MMPI style test but did CVSA rather than polygraph. As far as I can tell CVSA is even less scientific then the polygraph. I think the main appeal of the CVSA is that it's like a 40 hour certification and then just a microphone and some software you chuck on a laptop. All of the nonsense at a fraction of the cost!

A guy on my unit is one of the best cops I've ever worked with. Total straight arrow family man, good investigator, great tactical instincts, etc. He works for a city pd instead of the feds because he failed the FBI's polygraph during their hiring process.