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Posted by DStarbuck
- Dec 17, 2008, 12:01 AMThis thread was hijacked in a big manner!
Regarding the original post topic... It is VERY unlikely that anybody knows you posted here. Unless they confiscated your personal computer or something.
Regarding the original post topic... It is VERY unlikely that anybody knows you posted here. Unless they confiscated your personal computer or something.
Posted by Drew Richardson
- Jan 27, 2007, 03:22 PMLienot,
DLCQ's do in fact sidestep some of the problems with PLCQ's, but present some additional ones of their own. On the positive side, as you indicate, (1) the DLCQT does not require setting (beyond basic description and purpose) of the chosen DLQ's and further avoids the accompanying examiner deception/misrepresentation of the PLCQT as relates to the description of PLCQ's in the pre-test, (2) avoids some of the serious deficiencies of the PLCQT quality control process as outlined in my last response in this thread to LieBabyCryBaby, and (3) avoids some of the unnecessary trauma that innocent/non-deceptive examinees are subjected to and that occurs as a result of common practices that occur in both the pre-test and post-test phases of the PLQCT for even deemed to be NDI examinees.
The down side to the DLCQT relates basically to two issues: (1) countermeasures and (2) what I believe is the basic mechanism for ANS response for lie tests in general.
With regard to countermeasures, the would-be applicant of such procedures in a PLCQT is given but two tasks: (1) identify relevant and control questions, and (2) covertly produce appropriate responses to the latter. The first task is eliminated with the use of the DLCQT making the overall process that much easier for such an examinee.
The second and what I believe to be a fatal flaw relates to what I further believe is the underlying mechanism of polygraph question response in a lie test, that being fear of the consequences of having been found deceptive with regard to some important issue on the test. This is not to be confused with fear of being caught in a lie—this is really an academic issue—the real practical issue and concern for the examinee are the consequences of being thought to be deceptive (regardless of whether he/she actually is) to important issues. This, of course, is a relative issue as it relates to the inter-compared and scored relevant and control issues/questions. As I have stated many times in many places, I believe the relevant and control issues of a PLCQT are clearly distinguishable by the average examinee and that furthermore then consequences of being found deceptive to PLCQ's are both obvious and much less than the consequences of having been found deceptive to the relevant material in such a test. This consideration which would explain what I believe is the large occurrence of false positive exam results (particularly in a screening context) is only magnified in the DLCQT, in which the DLCQ's are intentionally made known to the examinee and for which the examinee is only following the instructions of the examiner who asks the examinee to lie to these questions (leading to the absence of any real or perceived consequences for the directed deception that occurs). It is for this latter reason that I believe all current paradigms for lie detection are flawed and highly recommend concealed information testing as an alternative.
DLCQ's do in fact sidestep some of the problems with PLCQ's, but present some additional ones of their own. On the positive side, as you indicate, (1) the DLCQT does not require setting (beyond basic description and purpose) of the chosen DLQ's and further avoids the accompanying examiner deception/misrepresentation of the PLCQT as relates to the description of PLCQ's in the pre-test, (2) avoids some of the serious deficiencies of the PLCQT quality control process as outlined in my last response in this thread to LieBabyCryBaby, and (3) avoids some of the unnecessary trauma that innocent/non-deceptive examinees are subjected to and that occurs as a result of common practices that occur in both the pre-test and post-test phases of the PLQCT for even deemed to be NDI examinees.
The down side to the DLCQT relates basically to two issues: (1) countermeasures and (2) what I believe is the basic mechanism for ANS response for lie tests in general.
With regard to countermeasures, the would-be applicant of such procedures in a PLCQT is given but two tasks: (1) identify relevant and control questions, and (2) covertly produce appropriate responses to the latter. The first task is eliminated with the use of the DLCQT making the overall process that much easier for such an examinee.
The second and what I believe to be a fatal flaw relates to what I further believe is the underlying mechanism of polygraph question response in a lie test, that being fear of the consequences of having been found deceptive with regard to some important issue on the test. This is not to be confused with fear of being caught in a lie—this is really an academic issue—the real practical issue and concern for the examinee are the consequences of being thought to be deceptive (regardless of whether he/she actually is) to important issues. This, of course, is a relative issue as it relates to the inter-compared and scored relevant and control issues/questions. As I have stated many times in many places, I believe the relevant and control issues of a PLCQT are clearly distinguishable by the average examinee and that furthermore then consequences of being found deceptive to PLCQ's are both obvious and much less than the consequences of having been found deceptive to the relevant material in such a test. This consideration which would explain what I believe is the large occurrence of false positive exam results (particularly in a screening context) is only magnified in the DLCQT, in which the DLCQ's are intentionally made known to the examinee and for which the examinee is only following the instructions of the examiner who asks the examinee to lie to these questions (leading to the absence of any real or perceived consequences for the directed deception that occurs). It is for this latter reason that I believe all current paradigms for lie detection are flawed and highly recommend concealed information testing as an alternative.
Posted by Lienot
- Jan 26, 2007, 06:01 PMDrew Richardson,
What is your opinion on the DLQ developed by the Utah group. There is not deception by the examiner, only from the examinee.
I do agree that QC should be done by an individual that does not know the original examiner or examiee, is not a member of the organization the examiner belongs to and only the data should be reviewed to avoid any possible knowledge of the case. Just a review of the data using the new DODPI rules for scoring?
What is your opinion on the DLQ developed by the Utah group. There is not deception by the examiner, only from the examinee.
I do agree that QC should be done by an individual that does not know the original examiner or examiee, is not a member of the organization the examiner belongs to and only the data should be reviewed to avoid any possible knowledge of the case. Just a review of the data using the new DODPI rules for scoring?
Posted by quickfix
- Jan 26, 2007, 11:36 AMLBCB: your points are well-taken; however, in a properly-conducted quality control procedure, one QC examiner alone cannot overcall a field evaluation, and further, should not even know who the examiner was. A proper QC review is an analysis of the data without any accompanying paperwork with the examiner's name, only a record or file number. If the first qc reviewer does not concur, it goes to a second look by another reviewer; the second reviewer does not know it was already reviewed and non-concurred with; he is evaluating the data as if he was the first look; if the second review non-concurs, then the exam is nont supported; if he does concur, it goes to a third review which in effect break the tie. Interestingly, if the first qc reviewer concurs with the field examiner that the examinee passed, case closed, which is actually a process favorable to the examinee. And yes, when DODPI scoring criteria changes, qc must follow suit and comply. I don't know what your program's qc process is like, but within DOD, that's how it's done. And when there's a perception that a qc reviewer doesn't like a particular examiner, a statistic review of how many times that qc person did not concur with that particular examiner, compared to other qc reviewers/examiners/etc, will bear that out. No program manager should tolerate a qc reviewer's bias toward an examiner he doesn't like; the only one who suffers is the examinee.
Posted by Drew Richardson
- Jan 26, 2007, 09:33 AMLieBabyCryBaby,
You write:
This and your immediately previous post on the subject/thread are perhaps the best posts of any polygrapher in the seven years of this message board's existence. Review of scoring by a second polygrapher is a straw-man activity. Polygraph chart scoring is fairly reliable (unless, as you point out, the community changes the rules midstream with new and better chart scoring criteria) and can be readily done by a third week polygraph student at DoDPI (at least when I was there).
The weak link as it were with control question test (CQT) polygraphy lies with the underlying theory and with what goes on during the pre-test setting of control questions, etc. Quite frankly, the polygraph community has no serious notion of what is the theoretical basis for the activity that they are engaged in which leaves it both collectively and individually with no objective measure of what they are trying to do with the setting of control questions and any real notion of when this might or might not be accomplished. Furthermore quality control groups with agencies such as the FBI (that do not audio/videotape their exams) are obviously relieved of such headaches (review of pre-test activity as well as meaningful review of allegations of impropriety, etc.) but are largely left with being engaged in such meaningless activity as to be embarrassing to any with a mind to reason and eyes to see.
You mention the notion of quality control review bias. As I mentioned before, I consider the present majority acitivity (chart rescoring) as an exercise of majoring on the minor. This is further made even more absurd with various biases that exist within quality control groups. In the mid 90's I was told that the Bureau's QC program was much more hesitant to overturn a DI call by the original examiner than a NDI opinion. As you can see and have pointed out, the combination of largely meaningless activity and bias leads to anything but quality control. Again, congratulations on your posts and shared insight. Regards...
You write:
Quote
Sorry, but Digithead is right on this one. "Quality Control" in polygraph is an exaggeration of what is done when one polygrapher takes a second look at the first polygrapher's charts. This isn't true "QC." It is merely giving one polygrapher--who is often no more skilled at data analysis than the other--the power to say whether the first polygrapher's data analysis was correct. It might serve as a CYA (cover your ass) for the polygrapher who conducted the test because he/she can always claim that someone else (the "QC") made the final call, but it isn't true quality control.
When I have conducted "quality control," I have always tried to be as objective as possible, but I have seen instances where other "QC" people are much more subjective. Sometimes there are egos involved. Sometimes the "QC" might not like the polygrapher who conducted the exam. I have seen instances where the "QC" went to a different polygraph school than the conducting polygrapher, or when the "QC" was taught a particular set of testing criteria and the conducting polygrapher was taught another, and they argued over how the data should be analyzed. Just recently, as George Maschke pointed out on this forum, the Dept. of Defense Polygrapher Institute recently changed its data analysis criteria, eliminating or revising various criteria. Now isn't that interesting? What do you suppose might happen when a newly graduated polygrapher, trained in the new criteria, goes up against a "QC" who was trained with the old criteria?
When "QC" is given the power to advise and to suggest, that is probably a good thing. But when "QC" is given the power to override, sometimes it may not be a good thing at all. I have witnessed extremely close calls on polygraph exams where the conducting polygrapher gave the benefit of the doubt to the examinee, only to have the "QC" then turn around and be much more picky and take that benefit of the doubt away. I have also seen conducting polygraphers fail an examinee, only to have the "QC" then turn around and give the examinee the benefit of the doubt.
You think that watching a video of the exam and then critiquing the performance is "quality control"? Perhaps. But perhaps it is simply one polygrapher watching another polygrapher's performance and subjectively deciding if he/she likes it. If the polygrapher's performance conforms well enough to what the "QC" does in his or her own exams, then approval is probably granted. But if the "QC" just doesn't like the polygrapher's style, what do you think might happen? How objective do you think this process is?
The point is, when you have this type of "QC," you don't really have quality control. You simply have two subjective viewpoints, with the "QC" being given the power to override the conducting polygrapher based not on the entirety of the exam, but simply on the chart analysis. Who do you think is apt to be more blind in this case--the polygrapher who conducted the entire process and THEN analyzed the data, or the "QC" who wasn't there and analyzes only the data? One might say that the "QC" won't be biased by the polygrapher/examinee interaction that took place during the exam, but one might also say that the "QC" won't benefit from a complete picture.
My point is not to ridicule the so-called "quality control" process conducted in the polygraph community, but rather to show that it isn't quality control at all.
This and your immediately previous post on the subject/thread are perhaps the best posts of any polygrapher in the seven years of this message board's existence. Review of scoring by a second polygrapher is a straw-man activity. Polygraph chart scoring is fairly reliable (unless, as you point out, the community changes the rules midstream with new and better chart scoring criteria) and can be readily done by a third week polygraph student at DoDPI (at least when I was there).
The weak link as it were with control question test (CQT) polygraphy lies with the underlying theory and with what goes on during the pre-test setting of control questions, etc. Quite frankly, the polygraph community has no serious notion of what is the theoretical basis for the activity that they are engaged in which leaves it both collectively and individually with no objective measure of what they are trying to do with the setting of control questions and any real notion of when this might or might not be accomplished. Furthermore quality control groups with agencies such as the FBI (that do not audio/videotape their exams) are obviously relieved of such headaches (review of pre-test activity as well as meaningful review of allegations of impropriety, etc.) but are largely left with being engaged in such meaningless activity as to be embarrassing to any with a mind to reason and eyes to see.
You mention the notion of quality control review bias. As I mentioned before, I consider the present majority acitivity (chart rescoring) as an exercise of majoring on the minor. This is further made even more absurd with various biases that exist within quality control groups. In the mid 90's I was told that the Bureau's QC program was much more hesitant to overturn a DI call by the original examiner than a NDI opinion. As you can see and have pointed out, the combination of largely meaningless activity and bias leads to anything but quality control. Again, congratulations on your posts and shared insight. Regards...
Posted by LieBabyCryBaby
- Jan 26, 2007, 12:35 AMQuote from: quickfix on Jan 25, 2007, 08:35 PMNot to beat a dead horse, but quality control offices (for those programs that have one), do more than conduct blind analysis. The responsibilities also include monitoring examiner performance, either live or reviewing audio/video tapes, and looking into complaints of misconduct against examiners. I have sat on several decertification boards (unfortunately) where my office has revoked the polygraph certification of incompetant or unethical examiners.
Sorry, but Digithead is right on this one. "Quality Control" in polygraph is an exaggeration of what is done when one polygrapher takes a second look at the first polygrapher's charts. This isn't true "QC." It is merely giving one polygrapher--who is often no more skilled at data analysis than the other--the power to say whether the first polygrapher's data analysis was correct. It might serve as a CYA (cover your ass) for the polygrapher who conducted the test because he/she can always claim that someone else (the "QC") made the final call, but it isn't true quality control.
When I have conducted "quality control," I have always tried to be as objective as possible, but I have seen instances where other "QC" people are much more subjective. Sometimes there are egos involved. Sometimes the "QC" might not like the polygrapher who conducted the exam. I have seen instances where the "QC" went to a different polygraph school than the conducting polygrapher, or when the "QC" was taught a particular set of testing criteria and the conducting polygrapher was taught another, and they argued over how the data should be analyzed. Just recently, as George Maschke pointed out on this forum, the Dept. of Defense Polygrapher Institute recently changed its data analysis criteria, eliminating or revising various criteria. Now isn't that interesting? What do you suppose might happen when a newly graduated polygrapher, trained in the new criteria, goes up against a "QC" who was trained with the old criteria?
When "QC" is given the power to advise and to suggest, that is probably a good thing. But when "QC" is given the power to override, sometimes it may not be a good thing at all. I have witnessed extremely close calls on polygraph exams where the conducting polygrapher gave the benefit of the doubt to the examinee, only to have the "QC" then turn around and be much more picky and take that benefit of the doubt away. I have also seen conducting polygraphers fail an examinee, only to have the "QC" then turn around and give the examinee the benefit of the doubt.
You think that watching a video of the exam and then critiquing the performance is "quality control"? Perhaps. But perhaps it is simply one polygrapher watching another polygrapher's performance and subjectively deciding if he/she likes it. If the polygrapher's performance conforms well enough to what the "QC" does in his or her own exams, then approval is probably granted. But if the "QC" just doesn't like the polygrapher's style, what do you think might happen? How objective do you think this process is?
The point is, when you have this type of "QC," you don't really have quality control. You simply have two subjective viewpoints, with the "QC" being given the power to override the conducting polygrapher based not on the entirety of the exam, but simply on the chart analysis. Who do you think is apt to be more blind in this case--the polygrapher who conducted the entire process and THEN analyzed the data, or the "QC" who wasn't there and analyzes only the data? One might say that the "QC" won't be biased by the polygrapher/examinee interaction that took place during the exam, but one might also say that the "QC" won't benefit from a complete picture.
My point is not to ridicule the so-called "quality control" process conducted in the polygraph community, but rather to show that it isn't quality control at all.
Posted by digithead
- Jan 25, 2007, 08:43 PMQuote from: quickfix on Jan 25, 2007, 08:35 PMNot to beat a dead horse, but quality control offices (for those programs that have one), do more than conduct blind analysis. The responsibilities also include monitoring examiner performance, either live or reviewing audio/video tapes, and looking into complaints of misconduct against examiners. I have sat on several decertification boards (unfortunately) where my office has revoked the polygraph certification of incompetant or unethical examiners.
Again, what you're stating is still within the purview of auditing and uniformity of process, not true QA/QC that occurs in engineering and science because you have no way of establishing ground truth and every subject serves as their own baseline. Hence, there are no standards on which to determine if someone's physiological responses are really indicative of deception. Ergo, true QA/QC can never be attained in a polygraph beyond uniformity of process...
Posted by quickfix
- Jan 25, 2007, 08:35 PMNot to beat a dead horse, but quality control offices (for those programs that have one), do more than conduct blind analysis. The responsibilities also include monitoring examiner performance, either live or reviewing audio/video tapes, and looking into complaints of misconduct against examiners. I have sat on several decertification boards (unfortunately) where my office has revoked the polygraph certification of incompetant or unethical examiners.
Posted by LieBabyCryBaby
- Jan 25, 2007, 10:47 AMDigithead is correct: The term "quality control" is actually a misnomer for the "second look" that is conducted by another polygrapher in many agencies. The polygraph "quality control" is nothing more than a second examiner scoring the same polygraph data a second time to make sure the first examiner's analysis is correct and his/her test was conducted within the acceptable measurement peramiters.
The polygraph process is often touted by insiders as a "scientific" process, and no doubt there is much science involved. There is also much theory involved, and there is an "art" to conducting a good polygraph exam. Therefore, using terms such as "quality control," "scientific process," and "art" to describe the polygraph process are a bit of a stretch if you define those terms by their true definitions, or even by their generally accepted definitions.
The polygraph process is often touted by insiders as a "scientific" process, and no doubt there is much science involved. There is also much theory involved, and there is an "art" to conducting a good polygraph exam. Therefore, using terms such as "quality control," "scientific process," and "art" to describe the polygraph process are a bit of a stretch if you define those terms by their true definitions, or even by their generally accepted definitions.
Posted by EosJupiter
- Jan 25, 2007, 05:17 AMDigithead,
Not to argue with you, but does not the polygraph industry and supporters tout the machine and its process as a science. If this is true, then it should be able to implement and pass true GC / IV&V scrutiny.
This is just another example of the polygraph not being able to standup to true scientific/engineering rigor. A toaster can pass this scrutiny, a polygraph cannot, with the exception of it passing the manufacturers operational test. Much success to you.
Regards EJ ...
Not to argue with you, but does not the polygraph industry and supporters tout the machine and its process as a science. If this is true, then it should be able to implement and pass true GC / IV&V scrutiny.
This is just another example of the polygraph not being able to standup to true scientific/engineering rigor. A toaster can pass this scrutiny, a polygraph cannot, with the exception of it passing the manufacturers operational test. Much success to you.
Regards EJ ...
Posted by digithead
- Jan 25, 2007, 02:34 AMQuote from: EosJupiter on Jan 24, 2007, 09:35 PMLBCB,
Quality Control on an inaccurate and subjective set of data (artifacts). Not to belittle the point, but QC on a polygraph is not even possible, if you know anything about QC and IV&V (Independent Verification and Validation) the premise of both techniques requires a known (proven process & stable data) result set with which to work against. Show me where in your polygraph process that is even possible. Not that I doubt your experience or judgement, no matter what you pro people say, your QC controls are no more than another smoke screen at trying to validate your process.
Regards ...
Eos,
Not to defend LBCB, but I think he's using QC in a different sense than what you're probably used to.
QC in this instance is basically an audit in that they have another examiner review a polygraph to simply ensure that the first examiner did what is required by their methodology. Also, with their schools and manuals they are attempting to solely get a "uniformity of process" rather than establishing that the machine is actually detecting lies based on an established sample.
This is different from a lab QA/QC process when you use NIST samples or other standards to make sure that the instrument is working correctly in addition to using a wide range of samples to ensure that the process works correctly between its detection limits. It is also different from manufacturing QA/QC where you sample from production lines to test if your products are conforming to standards.
I've seen other disciplines such as accounting and human resources misuse the term QC from what it originally meant in engineering/science.
Regards,
-digithead
Posted by EosJupiter
- Jan 24, 2007, 09:35 PMLBCB,
Quality Control on an inaccurate and subjective set of data (artifacts). Not to belittle the point, but QC on a polygraph is not even possible, if you know anything about QC and IV&V (Independent Verification and Validation) the premise of both techniques requires a known (proven process & stable data) result set with which to work against. Show me where in your polygraph process that is even possible. Not that I doubt your experience or judgement, no matter what you pro people say, your QC controls are no more than another smoke screen at trying to validate your process.
Regards ...
Quality Control on an inaccurate and subjective set of data (artifacts). Not to belittle the point, but QC on a polygraph is not even possible, if you know anything about QC and IV&V (Independent Verification and Validation) the premise of both techniques requires a known (proven process & stable data) result set with which to work against. Show me where in your polygraph process that is even possible. Not that I doubt your experience or judgement, no matter what you pro people say, your QC controls are no more than another smoke screen at trying to validate your process.
Regards ...
Posted by LieBabyCryBaby
- Jan 24, 2007, 08:51 PMAs I said, "Certified schools and quality control prorams are in place to try to minimize these weaknesses in the polygraph process."
These schools and quality control programs were set up to address the weaknesses I talked about in the polygraph process. If conducting the process in the optimal manner were easy, and if everyone who learned how to operate a polygraph machine could conduct the process with the same proficiency, then there would be no need for either of these things. The fact that they exist--to use a hackneyed phrase from this forum--"speaks volumes," don't you think?
These schools and quality control programs were set up to address the weaknesses I talked about in the polygraph process. If conducting the process in the optimal manner were easy, and if everyone who learned how to operate a polygraph machine could conduct the process with the same proficiency, then there would be no need for either of these things. The fact that they exist--to use a hackneyed phrase from this forum--"speaks volumes," don't you think?
Posted by fender85
- Jan 24, 2007, 07:11 PMHey LieBaby,
How can we make sure our examiner is skilled at what he is doing?
How can we make sure our examiner is skilled at what he is doing?
Posted by LieBabyCryBaby
- Jan 24, 2007, 06:49 PMArt in polygraph, as I am talking about, has to do with conducting the entire process with precision, finesse, and expertise. I'm not talking about being creative here. Creative art is something entirely different. The polygraph process IS scientific, in that there are certain scientific principles involved, and the data being monitored, measured and compared is certainly scientific data. However, there is also an "art" involved, and that is the art of interview/interrogation, as well as the art--or perhaps a better word would be skill--with which the polygrapher conducts the entire process, from greeting the examinee to writing good reports.
Don't assume that I don't know the weaknesses and limitations of the polygraph PROCESS. Because there are elements of skill, insight and, yes, intuition (oooh, there's a word that will definitely get a backlash from the anti- people) involved, the science can be affected by an examiner lacking in these elements. Also, I am well aware that innocent people may be hurt--as some of you claim to be--by a poorly conducted polygraph. But where YOU say it is "junk science," I would say it is simply a poorly conducted scientific process.
The problems with the polygraph, which I readily admit, are the following:
Polygraphers and examinees are of widely varying personalities, among other difficult-to-control factors such as education level, experience, expectations, etc.
Polygraphers vary in skill, i.e., "artistic ability."
The questions used on an exam, and the emphasis placed on each question by both the polygrapher and the examinee, vary. And I believe that in many cases an examinee can be oversensitized to particular questions, especially when he/she reads information found on this website and from other sources that tell the examinee that only certain issues (relevant issues) matter to the examiner.
And finally, the human mind and body are in a constant state of flux, which can create many other uncontrollable variables.
I admit all of these as weaknesses of the polygraph. Yet I can still be an advocate of the polygraph IF it is conducted by an "artful" and "scientific" examiner. Certified schools and quality control prorams are in place to try to minimize these weaknesses in the polygraph process, and I think these things work for the most part. If the conditions are right--which I believe they usually are because I have seen this through experience--the polygraph works almost all of the time.
You see, I understand all of these things because of my experience, not simply because I read some questionable lab study or obtain some secondhand knowledge from inexperienced sources. The polygraph works. Yes, it does. But without the "art" the science is questionable. But then you might say this about many other more scientific processes. If the person conducting the process isn't sufficiently skilled, and the conditions of the tools and the subject are not optimal, many scientific processes will fail or at least be hindered.
Don't assume that I don't know the weaknesses and limitations of the polygraph PROCESS. Because there are elements of skill, insight and, yes, intuition (oooh, there's a word that will definitely get a backlash from the anti- people) involved, the science can be affected by an examiner lacking in these elements. Also, I am well aware that innocent people may be hurt--as some of you claim to be--by a poorly conducted polygraph. But where YOU say it is "junk science," I would say it is simply a poorly conducted scientific process.
The problems with the polygraph, which I readily admit, are the following:
Polygraphers and examinees are of widely varying personalities, among other difficult-to-control factors such as education level, experience, expectations, etc.
Polygraphers vary in skill, i.e., "artistic ability."
The questions used on an exam, and the emphasis placed on each question by both the polygrapher and the examinee, vary. And I believe that in many cases an examinee can be oversensitized to particular questions, especially when he/she reads information found on this website and from other sources that tell the examinee that only certain issues (relevant issues) matter to the examiner.
And finally, the human mind and body are in a constant state of flux, which can create many other uncontrollable variables.
I admit all of these as weaknesses of the polygraph. Yet I can still be an advocate of the polygraph IF it is conducted by an "artful" and "scientific" examiner. Certified schools and quality control prorams are in place to try to minimize these weaknesses in the polygraph process, and I think these things work for the most part. If the conditions are right--which I believe they usually are because I have seen this through experience--the polygraph works almost all of the time.
You see, I understand all of these things because of my experience, not simply because I read some questionable lab study or obtain some secondhand knowledge from inexperienced sources. The polygraph works. Yes, it does. But without the "art" the science is questionable. But then you might say this about many other more scientific processes. If the person conducting the process isn't sufficiently skilled, and the conditions of the tools and the subject are not optimal, many scientific processes will fail or at least be hindered.