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Okay.

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Some PDs do drug testing, and that can offer some confirmation of polygraph.  I don't know how much of that has been published.  It's a good area to look at more closely.

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Tell that to the hundreds labeled as child molesters early in the process but were "saved" by those "safeguards."  My point is that there are errors in any system.  Failing a polygraph has, in most instances, limited costs.  The criminal system is heavily weighted in favor of the accused, yes, because the cost is so high.  However, the civil system is not, because the costs are lower: money verses liberty.  Look at OJ for example.

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This is where we disagree.  The process is not arbitrary.  How do you know the person is telling the truth?

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You do what you accuse polygraph examiners of doing as you can't know that is true.  That is why there is a desire for polygraph and truthfulness testing of all sorts.

That is the problem with your logic.  Consider this: Candidate A comes in for a job and "fails" his polygraph, being called a liar.  You say there's no way to know if that's true (and investigation may help), but we should accept the person's claim of innocence so you can compile your anecdotal data.  You accept his story based on your personal disbelief in polygraph screening, but to believe him requires you accept (blindly) that he's truthful.  Why is your way better?

Any test that discriminates truth from lies at better than chance rates, no matter how poor, is going to get your more accurate results than blindly accepting people's claims.

I did a study that I've yet to publish in which I found that about 50% of LE candidates disclose more drug involvement to the polygraph examiner than they do during the background / application process.  Not a single spy has been reported to have been caught based on an interview alone.  Those are factors that must be considered when determining the costs verses benefits of polygraph screening. 

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It could be that I don't know the numbers.

Barry_C wrote on Oct 31^st, 2007 at 1:50pm:

Are you suggesting that applicants fail the polygraph on drug-related questions, and the PD continues them through the application process to the medical test, where the presence of drugs are detected in their urine?  I think that scenario is unlikely, as applicants who fail their polygraph are immediately removed from the application process.

Possibly you are suggesting that people who pass their polygraph are then confirmed as drug users by urinalysis during medical screening?  I suppose that happens, but if and when it does it serves more to justify a lack of confidence in the accuracy of the polygraph than anything else.

Barry_C wrote on Oct 31^st, 2007 at 1:50pm:


I don’t follow you on this.  Tell what, exactly, to the hundreds labeled as child molesters?  That there are safeguards in place and a Constitutional guarantee of due process?  If they have already been “saved” by those safeguards, why would I need to tell them about those safeguards?


Barry_C wrote on Oct 31^st, 2007 at 1:50pm:

That is precisely my point.  I don’t know they are telling the truth any more than you know they are lying.  You could also simply disqualify a random 50% of all applicants using the same logic;  "We don't know they are telling the truth, so let's get rid of them."  If nobody knows, why disqualify them?  

After my own personal experiences with the polygraph, and having three different examiners look me straight in the eye and tell me they “knew” I was lying when I actually did know I was telling the truth, I have no reason to believe that an unproven accusation of deception by a polygraph examiner is any more credible than the corresponding protestation of innocence by a police applicant.  Again, if there's no proof either way, why disqualify them?

Barry_C wrote on Oct 31^st, 2007 at 1:50pm:


First of all, I am not compiling any anecdotal (or any other) data.  I have made reference to anecdotal data because you were so dismissive of it, and I believe that the majority of data used by polygraph examiners to justify their belief in the polygraph’s accuracy is simply anecdotal data.  If you dismiss the data offered by false positives because it is “merely” anecdotal data you should also dismiss the data offered by examiners, but you do not.

I don’t believe there is any problem with my logic.  If a police candidate fails his polygraph and there is no indication on the background investigation that he was lying about anything, I think it is far more logical and justifiable to believe him than it is to believe a pseudoscientific process that, in my own personal experience, was inaccurate three out of four times.  During the background investigation, detectives speak with people who have known the applicant for years, sometimes for his whole life.  If there is no indication from any of those people that the applicant is an unsuitable candidate, do you really feel it is logical to take the word of someone who met the applicant for the first time ever, interviewed him for an hour or two, and then concluded he was lying about drug use, or theft, or whatever?

Barry_C wrote on Oct 31^st, 2007 at 1:50pm:

I guess that depends on how you look at it.  I think the test would have to nearly perfect in order to be worthwhile.

If you have a test that is 60% accurate (which would be better than average chance) it will be inaccurate, on average, 40% of the time.  If you have one hundred applicants, how many do you believe will lie about something on their application?  Twenty?  Thirty?  Half?  Let’s say that 40 of them will lie about something, just for the sake of simplifying the math.

If the 60% accurate test functions normally, at the end of the test you will have 36 truthful people pass, and 24 truthful people fail.  You will also have 24 deceptive people fail, and 16 deceptive people pass.  

You will have a total of 52 people pass, and 48 people fail.  But of the people who passed, 16 of them lied and got away with it.  And out of the people who failed, 24 of them were telling the truth.

So now you are left with 52 applicants, nearly a third of which are liars who were able to defeat the test.  And out of the 48 people you booted from the application process, half of them were telling the truth and were disqualified for absolutely no reason whatsoever.

I don’t think that sort of process is fair or logical.  It allows too many liars to proceed and disqualifies too many truthful applicants.  It also provides a false sense of security because the 16 liars who just got sworn in as police officers are viewed as having already “passed” a test designed to detect deception.

Okay Ray,

You beat me to the punch.  I've been typing a line here and there (in Word) all day.  Here's my much similar response:

Sarge,

Is your glass always half empty?

Let’s look at the numbers and see what’s really what.

Assume you have 1000 candidates for 500 jobs.  Assume further that half of them have failed to disclose information at what would be the polygraph stage had the hiring agency had a polygraph program. Therefore, the base rate of “liars” is 50%.  (That’s not a figure I pulled out of thin air as you’ll recall that I have that data, which has yet to be published.)  Since this agency has no polygraph requirement, then chance will dictate which 50 get the job offers (as we’re at the end of the road as far as the hiring process goes.)

1000 candidates
50% base rate of liars
500 jobs
50% chance of catching liars (chance / coin flipping)

So, we’re going to end up hiring 250 liars (50%) and 250 truthful candidates (50%):

Truthful hired      = 250 (50% of 50 job applicants)
Liars hired      = 250 (50% of 50 job applicants)

If, however, we introduce polygraph, what will happen?  Assume a polygraph is 80% accurate.  (That number doesn’t come from thin air either.  There are a few studies on screening exams: the TES and the R/I.  Both exceed 80% accuracy, so this figure is conservative.  For those of you who aren’t data-driven, I can’t help you understand this.)

1000 candidates
50% base rate of liars
500 jobs
80% chance of catching liars with polygraph

Let’s do the math now:

Truthful hired      = 400 (80% of 50 polygraph NDI decision candidates – that are really truthful)

Liars hired      = 100 (20% of 50 polygraph NDI decision candidates – that are really liars)

400 truthful hired with polygraph – 250 hired without polygraph = 150 additional truthful hires.

150/250 = 60% more truthful people get jobs with polygraph that is 80% accurate if base rate of liars is 50%.

Let’s look at your figure, 60%, which the research shows to be a very conservative figure:

1000 candidates
50% base rate of liars
500 jobs
60% chance of catching liars with polygraph

Truthful hired      = 300 (60% of 500 polygraph NDI decision candidates – that are really truthful)

Liars hired      = 200 (40% of 500 polygraph NDI decision candidates – that are really liars)

50/250= 20% more truthful people get jobs with polygraph that is 60% accurate if base rate of liars is 50%.

So even with your 60% figure, the process is fairer to the truthful (on average) when all is said and done.  (Of course, the percentages are the same whether it’s 10 candidates and 5 jobs or 10,000 candidates and 5,000 jobs.)

Translation:

"I don't understand the math.  I don't understand statistics or research methodology.  I haven't read the research literature I've implied I have, and I haven't an intelligent and sound response, so I'll resort to name-calling."

I think most have figured that our already, but I am curious as to why you continue to post when you have nothing of substance to add to the discussion.

Do you have a problem with my math?  Have I presented it wrong?  What's the issue?  I suspect you don't really have one, but I'm willing to listen if you're up to the task.

The results of my polygraph were inclonclusive and I have to take it again. Can you define inconclusive when it comes to a poly result?

Thanks

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Statistics is a branch of applied mathematics.  You should have learned that in college.  Regardless, you haven't shown where I err in my math or reasoning.   

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That is true of a CQT.  Other testing techniques can result in in INC too.  In some situations it means you made a post-test admission to a question so further testing is necessary to clear the issue.  (Some would report it as deceptive; others, as I've explained.)

Barry_C wrote on Nov 1^st, 2007 at 7:26pm:


I think he punched you in the head. Your arithmetic (sorry Noodle, I mean your 'math') contains some elementary errors. I certainly hope that someone brighter than you checks out your research before you
publish it.

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No. it comes from the same place where they teach you that 80% of 50 = 400 


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Since when does 80% of 50 = 400 ???

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Since when does 20% of 50 = 100 ???
And so the BS continues......