FALSE syllogism?

[pailryder]

Mr Maschke

Of course I cherry pick my quotes, anyone here who doesn't?  My point is not that Dr Lykken supported polygraph.  No reader of Tremor could draw that conclusion.  My point was just that Lykken changed his mind on some issues and that at one point he seemed to at least try to give the appearance of objectivity.  But then he changed his mind about that too.

[pailryder]

Mr Maschke

What I found most interesting about Lykken's quote was his suggestion that in some cases, society may judge any improvement over chance, to outweigh the cost to the false positive.  I know that you would not grant that our techniques provide any improvement over chance, and I can understand how an individual false positive would hardly be presuaded, but this point is often given as the main reason some decide to request and submit to private crediability assessment.

[George W. Maschke]

pailryder,

The passage you quoted from (apparently the 1st edition of) A Tremor in the Blood is retained in the 2nd edition, where it appears at p. 68. For proper context, here's the entire section in which the passage appears:

How dependable is the lie detector, then? Here is a straightforward question for which there is no simple answer. Since "dependable" is vague and the "lie detector" does not exist, I must start by rewording the question. There are several different types of polygraphic examination, each based on different assumptions; one cannot assume that all these types will have the same degree of accuracy. To provide some initial perspective, remember the purpose of a polygraph is to diagnose the individual respondent as deceptive or truthful with greater accuracy than one could achieve without the examination. I can classify subjects as truthful or deceptive and be correct half the time merely by flipping a coin; the chance accuracy of this type of dichotomous classification is 50%--if 50% of the subjects are actually lying. If my subjects are all defendants who have been brought to trial on criminal charges, and if the statistics show that 80% of this group, on average, are in fact guilty, then I could attain 80% accuracy just by classifying everyone as deceptive. For a test to be useful, its accuracy must be obviously higher than one can achieve by chance, and it should usually be higher than the base rate of the more frequent classification in the group tested.

Finally, we must ponder the deeper question of how accurate a lie test ought to be for particular applications. If one is hiring policemen or CIA operatives, then it might be thought that any additional clues, any improvement over chance at all might be worthwhile. These are sensitive positions in which the wrong person can do great mischief, and it may be in the public interest to use a screening procedure that reduces the number of undesirable candidates hired, even if this means also excluding a large number of perfectly acceptable people, wrongly called deceptive by the test. As we shall see later, however, there is reason to believe that many honorable people, the very sort of "straight arrows" we should like to see in these sensitive positions, are especially vulnerable to failing and being eliminated by these screening tests. Moreover, cases like that of Aldrich Ames indicate that false negative errors (classifying a liar as truthful) not only occur but do great harm when reasonable suspicions are quieted by unjustified faith in the polygraph. In the United Nations fantasy that we considered earlier, it would be disastrous to settle for even 90% accuracy in the Truth Verifier. If so much weight is placed on the test result that one makes less effort to seek other information or is lulled into a feeling of great confidence in the result, then one should make sure that the test result is very dependable indeed.

I don't see how you can, in good faith, suggest than Lykken lacked objectivity in his foregoing assessments. Unlike polygraph operators, Lykken's judgment was unclouded by the self-interest involved when one derives income from giving lie detector tests.

[notguilty1]

pailryder,

The passage you quoted from (apparently the 1st edition of) A Tremor in the Blood is retained in the 2nd edition, where it appears at p. 68. For proper context, here's the entire section in which the passage appears:

How dependable is the lie detector, then? Here is a straightforward question for which there is no simple answer. Since "dependable" is vague and the "lie detector" does not exist, I must start by rewording the question. There are several different types of polygraphic examination, each based on different assumptions; one cannot assume that all these types will have the same degree of accuracy. To provide some initial perspective, remember the purpose of a polygraph is to diagnose the individual respondent as deceptive or truthful with greater accuracy than one could achieve without the examination. I can classify subjects as truthful or deceptive and be correct half the time merely by flipping a coin; the chance accuracy of this type of dichotomous classification is 50%--if 50% of the subjects are actually lying. If my subjects are all defendants who have been brought to trial on criminal charges, and if the statistics show that 80% of this group, on average, are in fact guilty, then I could attain 80% accuracy just by classifying everyone as deceptive. For a test to be useful, its accuracy must be obviously higher than one can achieve by chance, and it should usually be higher than the base rate of the more frequent classification in the group tested.

Finally, we must ponder the deeper question of how accurate a lie test ought to be for particular applications. If one is hiring policemen or CIA operatives, then it might be thought that any additional clues, any improvement over chance at all might be worthwhile. These are sensitive positions in which the wrong person can do great mischief, and it may be in the public interest to use a screening procedure that reduces the number of undesirable candidates hired, even if this means also excluding a large number of perfectly acceptable people, wrongly called deceptive by the test. As we shall see later, however, there is reason to believe that many honorable people, the very sort of "straight arrows" we should like to see in these sensitive positions, are especially vulnerable to failing and being eliminated by these screening tests. Moreover, cases like that of Aldrich Ames indicate that false negative errors (classifying a liar as truthful) not only occur but do great harm when reasonable suspicions are quieted by unjustified faith in the polygraph. In the United Nations fantasy that we considered earlier, it would be disastrous to settle for even 90% accuracy in the Truth Verifier. If so much weight is placed on the test result that one makes less effort to seek other information or is lulled into a feeling of great confidence in the result, then one should make sure that the test result is very dependable indeed.

I don't see how you can, in good faith, suggest than Lykken lacked objectivity in his foregoing assessments. Unlike polygraph operators, Lykken's judgment was unclouded by the self-interest involved when one derives income from giving lie detector tests.

"I don't see how you can, in good faith, suggest than Lykken lacked objectivity in his foregoing assessments. Unlike polygraph operators, Lykken's judgment was unclouded by the self-interest involved when one derives income from giving lie detector tests".

And here "lies" (no pun intended) the motivation for Sackett and his like to  continue to defend a un scientific test that yeilds results that CANNOT be relied upon for the purpose of dedtecting decption.
Their unwillngness to admit that the test is not accurate though they use verbage at times that would suggest. This is due manly to the financial ties they have to polygraph and that is also why they are always on here trying to BS new members to this site to continue to believe that polygraph is 95-98 % accurate.

[sackett]

"notguilty1",

I hate to be the bearer of bad news, but as a public servant, I am not getting wealthy working for my agency and conducting polygraph examinations.  

I do this because I truly believe in the polygraph process.  You and others may continue to accuse examiners of supporting what we do as a financial concern and interest, but you are wrong.  

Most of us believe in what we are doing.  


Sackett

[pailryder]

ng1

To be fair, you must recognize that Dr. Lykken had some financial interest in selling books.    

[notguilty1]

"notguilty1",

I hate to be the bearer of bad news, but as a public servant, I am not getting wealthy working for my agency and conducting polygraph examinations.  

I do this because I truly believe in the polygraph process.  You and others may continue to accuse examiners of supporting what we do as a financial concern and interest, but you are wrong.  

Most of us believe in what we are doing.  


Sackett

I am sure your not getting wealthy. We all have our financial potential limitations.
If you as you say "really believe in the polygraph process" then you also have other limitaions and that is in comprehention of facts. Odd that some one that has those limitations is sitting in judgement of others.
Perhaps it the "sitting in judgement" that so apeals to you. You have shown by your posts that you recognize and accept the limitations of polygraph and you have even said that "this is all we have". So how can you possibly believe in the process?

[notguilty1]

ng1

To be fair, you must recognize that Dr. Lykken had some financial interest in selling books.    

I do recognize that. But you must know that his views are not unique in the subject of polygraph if he was the only one I would agree that finaicial motivation is a consideraton.
Come on ..... if polygraph was in fact 95-98% accurate or anything close it would be admissable in court and it would not be illegal for employers other than feds and LE to use it in their employment practice.

[sackett]

"notguilty1",

I hate to be the bearer of bad news, but as a public servant, I am not getting wealthy working for my agency and conducting polygraph examinations.  

I do this because I truly believe in the polygraph process.  You and others may continue to accuse examiners of supporting what we do as a financial concern and interest, but you are wrong.  

Most of us believe in what we are doing.  


Sackett

I am sure your not getting wealthy. We all have our financial potential limitations.
If you as you say "really believe in the polygraph process" then you also have other limitaions and that is in comprehention of facts. Odd that some one that has those limitations is sitting in judgement of others.
Perhaps it the "sitting in judgement" that so apeals to you. You have shown by your posts that you recognize and accept the limitations of polygraph and you have even said that "this is all we have". So how can you possibly believe in the process?

"notguilty1",

you presume to understand my motivations.    

I have stated that polygraph is not perfect and mistakes can be made, by either and/or both parties.  But, we have come to an agreement that nothing is perfect.  

Your (and others' point) is to do away with polygraph entirely because there is a small percentage of wrong findings.  While George and others attack polygraph on the primary basis that the NAS found it was too unstable as a screening device, althewhile ignoring potential motiviations and the fact it was not scientifc research but a review of material and research they thought appropriate; this entire board has ignored it's finding and potential concerning specific issue testing.  

Very selective, I think...

Sackett

[notguilty1]

"notguilty1",

I hate to be the bearer of bad news, but as a public servant, I am not getting wealthy working for my agency and conducting polygraph examinations.  

I do this because I truly believe in the polygraph process.  You and others may continue to accuse examiners of supporting what we do as a financial concern and interest, but you are wrong.  

Most of us believe in what we are doing.  


Sackett

I am sure your not getting wealthy. We all have our financial potential limitations.
If you as you say "really believe in the polygraph process" then you also have other limitaions and that is in comprehention of facts. Odd that some one that has those limitations is sitting in judgement of others.
Perhaps it the "sitting in judgement" that so apeals to you. You have shown by your posts that you recognize and accept the limitations of polygraph and you have even said that "this is all we have". So how can you possibly believe in the process?

"notguilty1",

you presume to understand my motivations.    

I have stated that polygraph is not perfect and mistakes can be made, by either and/or both parties.  But, we have come to an agreement that nothing is perfect.  

Your (and others' point) is to do away with polygraph entirely because there is a small percentage of wrong findings.  While George and others attack polygraph on the primary basis that the NAS found it was too unstable as a screening device, althewhile ignoring potential motiviations and the fact it was not scientifc research but a review of material and research they thought appropriate; this entire board has ignored it's finding and potential concerning specific issue testing.  

Very selective, I think...

Sackett

Sackett, I don't presume to understad your motives I was simply guessing, unlike you I have no crystal ball to tell me what people are thinking.
Also, I am not here to eliminate a viable test that would in fact detect deception if and when that test is avaliable. To use polygraph as a detection devise in spite if its limitations in that capacity is WRONG and therefore must be eliminated as such.
Of course that leaves you unemployed. I am sorry that that is where you'd find yourself but it does not merritt continuing a lie to the public.
BTW Sackett you always mentionthat we are so few as I can see you are the only one that is here going on and on about your snake oil.

[pailryder]

ng1

Even if polygraph techniques were 100% some would still object to their use.  This is more an argument about proper use than simply numbers.  

[notguilty1]

ng1

The reality is that even if polygraph techiques were 100% some would still object to their use.  This is more than an argument about numbers.  

Pail,
That is not the reality and if it were that "some" would object this site would not have the success it has.
I have not seen any such issues arise with let's say DNA testing why? Because it is an accurate test and there fore IS admissable in court.
You have a test that by all accounts is little more than a coin toss, your industry knows this and so do you. Thats why you and Sackett are here trying to defend your position on a test that has shown to be overwhelmingly unreliable in detecting deception. If you can find a true and proven use for polygraph we would no longer have this argument and this site would loose it's usefullness.

[pailryder]

ng1

I am not here to defend all use of polygraph, especially preemp screening.  I am here to learn.  I learn more by discussion with those opposed to what I do than with people who support what I do, and frankly, it is a more stimulating conversation.  Help me learn, you tell me, give me a number, how accurate would CQT have to be for you to consider it useful?

And about DNA, did you follow the OJ matter?

[notguilty1]

ng1

I am not here to defend all use of polygraph, especially preemp screening.  I am here to learn.  I learn more by discussion with those opposed to what I do than with people who support what I do, and frankly, it is a more stimulating conversation.  Help me learn, you tell me, give me a number, how accurate would CQT have to be for you to consider it useful?

And about DNA, did you follow the OJ matter?

Pail,
I really appreciate your apperant willingness to have an intelligent discussion.
As for how accurate I would want it to be, doesn't matter because it's current legally accepted accuracy makes the test inadmissable in court as well as illegal for most employment screenings.
That to me makes it unacceptable no matter what the numbers are.
The Polygraph industry keeps claiming 95-98% ( I know this because that was told to me by the police examiner) which is non verifiable offically anywhere in any scientific study.
As for the OJ case if I recall the blood found at the scene was verified to be OJ's through DNA however he got off because of a very expensive defense team and sloppy police work not the failure of DNA analisis.

[pailryder]

notguilty 1

I guess I don't understand your beef.  You were a suspect in a theft, you consented to a police polygraph, the police examiner got your result wrong and subjected you to a harsh interrogation.  Is that what happened?  As Mr Maschke explains in The Lie Behind the Lie the only sure way of protecting against examiner error is to refuse the test.  So are you angry because your examiner understated the risk, or because he made an error, or because you didn't exercise your right to refuse?