- Welcome to AntiPolygraph.org Message Board.
A forum for free and open discussion of polygraph-related topics
Posted by 1904
- Oct 30, 2007, 11:11 AMQuote from: Hunter on Oct 28, 2007, 04:33 PMAccording to your logic, fingerprints should never be used, they are not 100% accurate when you include the inconclusive rate.Somewhere there is a fallacy in your logic. Maybe you should re evaluate what you have posted and see if you can correct it.
Hunter:
Re-evaluate what you said.
In the fingerprinting exercise there were 0 errors.
The correct calls are verifiable by direct comparison, there can be no error in the lab nor the field.
In a lab setting with students, errors and correct calls can be verified.
In the field however, correct calls and errors can seldom be verified.
That was the crux of Sarge's post. Unless your subject verified for you - you dont actually know.
You only THINK that you know.
And history tells us that many examiners thought wrong.
Posted by 1904
- Oct 30, 2007, 08:41 AMQuote from: Sergeant1107 on Oct 29, 2007, 09:07 PM
My post was meant to show that a person who uses the polygraph to screen potential employees need not have a belief in the ability of the polygraph to detect deception.
I have personally spoken with two chiefs of police in Connecticut (where polygraph screening for police officers is required by law) who said they are aware the polygraph cannot "detect lies", but that it can be effective at getting applicants to admit to various things.
Now there's some ground truth for the statisticians and pseudo scientists that daily swamp this board with pie-in-the-sky psychobabble and even though some declare that the AP folk bore them, continually
return with their daily tsunami dose of BS.
Posted by Sergeant1107
- Oct 29, 2007, 09:07 PMQuote from: EJohnson on Oct 29, 2007, 12:06 PMSo does your question imply that a person who was falsy accused of lying could then go on to use the instrument in the way that you stated? Unlikely. You have no faith in poly screening per your historic statements, so I gather that you wouldn't use the poly if it were your multi-million dollar operation. Call me crazy.My post was meant to show that a person who uses the polygraph to screen potential employees need not have a belief in the ability of the polygraph to detect deception.
I have personally spoken with two chiefs of police in Connecticut (where polygraph screening for police officers is required by law) who said they are aware the polygraph cannot "detect lies", but that it can be effective at getting applicants to admit to various things.
Posted by EJohnson
- Oct 29, 2007, 12:30 PMI wasn't endorsing E Prince and my point was that despite Prince's obvious controversial history, power, and alliances---and having failed his CIA polygraph which according to many people here----cost him a job by virtue of the stated draconian practices of "DI means DQ", he would seem to be the cat who would not use polygraph, rather than hiring 100's of us.
FYI, I'm not a huge Blackwater fan these days---but besides the point.
FYI, I'm not a huge Blackwater fan these days---but besides the point.
Posted by 1904
- Oct 29, 2007, 12:22 PMQuote from: EJohnson on Oct 29, 2007, 09:21 AM
I find it quite telling that now that he (Erik Prince) has such high accesses and clearences, that he continues to use polygraph pervasively within the Blackwater organization. Bare in mind that Prince calls the shots and he has a love affair with applicant screening modalities, and if he felt that polygraph was a pseudoscience he would certainly ignore the usage potentials.
I would hardly think that Erik Prince should be polygraph's poster boy.
Bad choice mate.
[/quote]
Posted by EJohnson
- Oct 29, 2007, 12:06 PMQuote from: Sergeant1107 on Oct 29, 2007, 11:53 AMQuote from: EJohnson on Oct 29, 2007, 09:21 AMBare in mind that Prince calls the shots and he has a love affair with applicant screening modalities, and if he felt that polygraph was a pseudoscience he would certainly ignore the usage potentials.
Don't you believe there is the distinct possibility that he, like many others, believe the polygraph is incapable of detecting truth or deception, but that it does serve to elicit damaging confessions from people who believe it will "detect lies?"
Using the polygraph in such a manner is hardly an endorsement of its scientific legitimacy. If Blackwater was screening employees who believed that a crystal ball could detect lies the crystal ball would be exactly as effective as the polygraph in eliciting confessions, and it would be exactly as capable of detecting truth or decption.
So does your question imply that a person who was falsy accused of lying could then go on to use the instrument in the way that you stated? Unlikely. You have no faith in poly screening per your historic statements, so I gather that you wouldn't use the poly if it were your multi-million dollar operation. Call me crazy.
Posted by Sergeant1107
- Oct 29, 2007, 11:53 AMQuote from: EJohnson on Oct 29, 2007, 09:21 AMBare in mind that Prince calls the shots and he has a love affair with applicant screening modalities, and if he felt that polygraph was a pseudoscience he would certainly ignore the usage potentials.
Don't you believe there is the distinct possibility that he, like many others, believe the polygraph is incapable of detecting truth or deception, but that it does serve to elicit damaging confessions from people who believe it will "detect lies?"
Using the polygraph in such a manner is hardly an endorsement of its scientific legitimacy. If Blackwater was screening employees who believed that a crystal ball could detect lies the crystal ball would be exactly as effective as the polygraph in eliciting confessions, and it would be exactly as capable of detecting truth or decption.
Posted by EJohnson
- Oct 29, 2007, 09:21 AMQuote from: 1904 on Oct 29, 2007, 08:45 AMQuote from: Hunter on Oct 27, 2007, 05:47 PM
Polygraph -18 correct identifications, 1 error and 1 inconclusive result for an over all accuracy of 95%QuoteIf in field testing the 5% Incon are called NDI, the error rate is 10%Error rates are too high for what C? Despite the disinformation, decisions regarding incarceration and/or applicant rejection as a sole result of polygraph are simply not tolerated, period. Perhaps your concern for "human collateral" stems from a modality from a seperate country---not in the US at this time. So many people are rejected by fed intel and cop shops because the officials seek individuals who are cleaner (can you say boringingly squeeky) than the vast majority of US citizens---in the scope of drugs, sexual history, and theft especially. Let a dog lick your balls as a teen?...well, the chief might not like that ----regardless if it was a typical teenage fancy. Steal cash from grandma while she was in the hospitol?--the cheif might have a soft spot for grandmothers-----but typically many things are overlooked unless they present as unashamed or perpetuating. Individuals, say, in an applicant screening situation, are rejected over many factors---many of which are not told to the applicant, as this is certainly the case with any job whether poly is used or not. Most times the applicant just doesn't have all the right qualities, and the polygraph is scapegoated. Take Erik Prince, the controversial owner and (former Navy Seal) of Blackwater USA, he failed his CIA poly, but it is pretty much accepted that he snagged other concerns--having garnered the reputation of being critical of the Naval Institue as a young attendee (he quit bitterly), and being a right-wing extremist (long story) among other slightly "off" personal attributes such as alleged recklessness (the CIA's greatest phobia)-------but was only told at that time that he simply "failed" his polygraph (according to the latest Newsweek magazine article on Blackwater's Prince.) I find it quite telling that now that he has such high accesses and clearences, that he continues to use polygraph pervasively within the Blackwater organization. Bare in mind that Prince calls the shots and he has a love affair with applicant screening modalities, and if he felt that polygraph was a pseudoscience he would certainly ignore the usage potentials.
That is too high in terms of human collateral.
In reality, the errors in field testing are likely to be considerably in excess of 10%.
The NAS study said as much, I'm just too lazy to find the link right now.
Whether error rates are attributable to the polygraph itself, or to inept examiners is disputable.
My humble opinion is that far too many examiners are gung ho, aggressive and inept.
Aspects that have been highlighted many times by reversed incarcerations and by some who post on this board.
ps. 1904, your opinion has never been "humble" and neither has mine.
Posted by 1904
- Oct 29, 2007, 08:45 AMQuote from: Hunter on Oct 27, 2007, 05:47 PM
Polygraph -18 correct identifications, 1 error and 1 inconclusive result for an over all accuracy of 95%
If in field testing the 5% Incon are called NDI, the error rate is 10%
That is too high in terms of human collateral.
In reality, the errors in field testing are likely to be considerably in excess of 10%.
The NAS study said as much, I'm just too lazy to find the link right now.
Whether error rates are attributable to the polygraph itself, or to inept examiners is disputable.
My humble opinion is that far too many examiners are gung ho, aggressive and inept.
Aspects that have been highlighted many times by reversed incarcerations and by some who post on this board.
Posted by Barry_C
- Oct 28, 2007, 06:26 PMYou're looking for influenza or an absence of influenza, just as you are looking for deception or an absence of deception. In both tests, you will have inconclusives. Just because you call the absence of deception "truth" (which it is), doesn't make them (or rather, the analogy) all that different. After all, you could call the absence of influenza "healthy" (and influenza, "sick").
Posted by Hunter
- Oct 28, 2007, 04:33 PMAccording to your logic, fingerprints should never be used, they are not 100% accurate when you include the inconclusive rate.Somewhere there is a fallacy in your logic. Maybe you should re evaluate what you have posted and see if you can correct it.
Posted by Sergeant1107
- Oct 28, 2007, 03:18 AMLooking at this from a layman's point of view, it seems that in every polygraph exam the subject is either being truthful or deceptive. The results of the polygraph should be a binary solution set; either truthful or deceptive. If you polygraph one hundred subjects, correctly identify one as DI or NDI, and score the other ninety-nine as inconclusive, I don't see how that can indicate the polygraph is 100% accurate. I think that would indicate the polygraph is 1% accurate, according to those numbers.
If you want to compare it to a medical diagnosis, you would have to compare it to a test that looks to identify the presence of one specific thing. You would want to compare it to a test that also had results in a binary solution set. If you tested one hundred people for the presence of influenza, and you correctly diagnosed one person as having the virus, but said you simply didn't know about the other ninety-nine, I don't think you'd be saying the influenza test was 100% accurate. An accurate test for the presence of influenza would either detect the presence of the virus or confirm that the virus was not present.
It seems like a given that in every polygraph the subject is either being truthful or deceptive. If the subjects in the study were asked a question such as, "Did you steal the contents of the package," it is likely they would all answer that they did not. Their denial would either be truthful or a lie. A test purported to detect deception should be able to determine which it is.
If you want to compare it to a medical diagnosis, you would have to compare it to a test that looks to identify the presence of one specific thing. You would want to compare it to a test that also had results in a binary solution set. If you tested one hundred people for the presence of influenza, and you correctly diagnosed one person as having the virus, but said you simply didn't know about the other ninety-nine, I don't think you'd be saying the influenza test was 100% accurate. An accurate test for the presence of influenza would either detect the presence of the virus or confirm that the virus was not present.
It seems like a given that in every polygraph the subject is either being truthful or deceptive. If the subjects in the study were asked a question such as, "Did you steal the contents of the package," it is likely they would all answer that they did not. Their denial would either be truthful or a lie. A test purported to detect deception should be able to determine which it is.
Posted by Brettski
- Oct 28, 2007, 03:10 AMQuote from: Barry_C on Oct 27, 2007, 05:37 PMIf we counted "inconclusives" as errors, then coin-flipping would be more accurate than fingerprinting - and I think those cited numbers are high for what I've seen in the field.
If your doctor said he didn't know what was wrong with you after one test, would he be wrong in his diagnosis? Wait, there is no diagnosis.
I agree, inconclusive results should not be classified as errors. There are plenty of stronger arguments against polygraphs without approaching an argument that is an easy win for pro-polygraphs. However, if inconclusive results weren't held against the examinee as the APA claims, then hypothetically it should be possible for an applicant to get nothing but inconclusive results on a polygraph screening tests, and still get hired by XYZ governement agency. To my understanding, this is not the case.
Posted by raymond.nelson
- Oct 27, 2007, 09:48 PMThis is a good example of some of the complexities surrounding the generic term "accuracy."
digithead has alluded to this before, though the discussion is grossly incomplete.
Test designers know that all tests are imperfect, and have identifiable limitations in terms of types of accuracy they can achieve.
Accuracy with inconclusives included is commonly referred to as sensitivity and specificity. Accuracy without inconclusives might be thoughts of as NPV or PPV. Of course, calculation methods for these statistics can differ, and includes within-set and cross-set variants, depending on your bayesian or inferential emphasis or orientation, and the exact question which one seeks to answer.
One of the dangers here is the gross error of substituting classification accuracy (sometimes called PPV or NPV), for the likelihood or probability of a correct classification of any single case. They are not at all the same according to some of the more common systems of mathematical thinking.
Fingerprinting is a good example of a test with very low sensitivity, but very high accuracy. With some tests, like fingerprinting, specificity is of little interest. Positive matches are the only result of any usefulness.
more later.
r
digithead has alluded to this before, though the discussion is grossly incomplete.
Test designers know that all tests are imperfect, and have identifiable limitations in terms of types of accuracy they can achieve.
Accuracy with inconclusives included is commonly referred to as sensitivity and specificity. Accuracy without inconclusives might be thoughts of as NPV or PPV. Of course, calculation methods for these statistics can differ, and includes within-set and cross-set variants, depending on your bayesian or inferential emphasis or orientation, and the exact question which one seeks to answer.
One of the dangers here is the gross error of substituting classification accuracy (sometimes called PPV or NPV), for the likelihood or probability of a correct classification of any single case. They are not at all the same according to some of the more common systems of mathematical thinking.
Fingerprinting is a good example of a test with very low sensitivity, but very high accuracy. With some tests, like fingerprinting, specificity is of little interest. Positive matches are the only result of any usefulness.
more later.
r
Posted by Hunter
- Oct 27, 2007, 05:47 PMSo lets include the inconclusives and you have the following figures, and polygraph really wins big time Sgt.
Polygraph -18 correct identifications, 1 error and 1 inconclusive result for an over all accuracy of 95%
18=90% Correct
1= 5% Inconclusive
1=5%. Incorrect
Handwriting – 17 correct identifications, 1 error and 2 inconclusive results for an overall accuracy of 94%.
17=85%
1= 5%
2+10%
Eyewitness – 7 correct identifications, 4 errors and 9 inconclusive results for an over all accuracy of 64%.
7=35%
4=20%
9=45%
Fingerprints – 4 correct identifications, 0 errors and 16 inconclusive results for an overall accuracy of 100%.
4=20%
0=0%
16=80%
Polygraph -18 correct identifications, 1 error and 1 inconclusive result for an over all accuracy of 95%
18=90% Correct
1= 5% Inconclusive
1=5%. Incorrect
Handwriting – 17 correct identifications, 1 error and 2 inconclusive results for an overall accuracy of 94%.
17=85%
1= 5%
2+10%
Eyewitness – 7 correct identifications, 4 errors and 9 inconclusive results for an over all accuracy of 64%.
7=35%
4=20%
9=45%
Fingerprints – 4 correct identifications, 0 errors and 16 inconclusive results for an overall accuracy of 100%.
4=20%
0=0%
16=80%