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  Can Comparison's be to strong?

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Author Topic:   Can Comparison's be to strong?
john fyffe
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posted 02-18-2013 01:29 PM     Click Here to See the Profile for john fyffe     Edit/Delete Message
just getting a conversation started?
Jim jump in any time.

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Ted Todd
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posted 02-18-2013 08:05 PM     Click Here to See the Profile for Ted Todd     Edit/Delete Message
Yes.

Next question please.

Ted

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Barry C
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posted 02-18-2013 08:20 PM     Click Here to See the Profile for Barry C   Click Here to Email Barry C     Edit/Delete Message
Define "too strong." Whatever it means, how would you ever know?

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skipwebb
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posted 02-19-2013 08:52 AM     Click Here to See the Profile for skipwebb   Click Here to Email skipwebb     Edit/Delete Message
I think you can make a comparison question "relevant" or too emotional and as a result, it could overshadow the relevant issue even in a deceptive person. I personally feel that both comparison questions and relevant questions are actually "relevant". They are just relevant to different people (quilty/innocent).

An example might be on a simple use of drug relevant issue test. If you were to use a drug distribution comparison question you might be asking a question far more relevant to the examinee than simple use.

The same might be the case if you were asking about the sexual molestation or fondling of a child and used a comparsion question that incorporates in its time frame, an older child in the family that he might also have molested at an earlier date.

But Barry is right, how would you know? You would have a false negative result and call the person NDI.

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Bill2E
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posted 02-19-2013 11:23 AM     Click Here to See the Profile for Bill2E   Click Here to Email Bill2E     Edit/Delete Message
Backster mentioned this and suggested if you are getting a reaction to both controls and relevant, weaken your control. I have seen, some years ago, reaction to both. My opinion about the cause was asking controls that did incorporate an element of the relevant issue. Since the 80's we have taught to separate the relevant and control questions so the controls don't incorporate the relevant issue.

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john fyffe
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posted 02-19-2013 11:34 AM     Click Here to See the Profile for john fyffe     Edit/Delete Message
Bill2e,

If you weaken your controls are you setting your examinee up to fail?

Which is better to hang an innocent man or let a guilty man go free?

Good day to all

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Bill2E
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posted 02-19-2013 01:00 PM     Click Here to See the Profile for Bill2E   Click Here to Email Bill2E     Edit/Delete Message
The answer is yes, you are setting up a situation in which the NDI may show DI. However Cleve Backsters thought on this was, if your getting any reaction to the relevant, the controls are competing, therefore weaken the controls. later examiners were taught to simply score the charts and avoid using control questions that overlap or are in the same category as the relevant.

This is Skip's post and only copied it:

"An example might be on a simple use of drug relevant issue test. If you were to use a drug distribution comparison question you might be asking a question far more relevant to the examinee than simple use.

The same might be the case if you were asking about the sexual molestation or fondling of a child and used a comparsion question that incorporates in its time frame, an older child in the family that he might also have molested at an earlier date."

[This message has been edited by Bill2E (edited 02-19-2013).]

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Barry C
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posted 02-19-2013 04:40 PM     Click Here to See the Profile for Barry C   Click Here to Email Barry C     Edit/Delete Message
First, you've not defined "too strong."

If the relevant and the comparison are both getting reactions (which is the norm from what I've seen), why assume it's the CQ that is the issue? Maybe it's the RQ? What evidence do you have that it is one over the other?

How do you "weaken" a CQ to allow the examinee to fail properly? After all, you've already decided that's the way it is going to go.

The jury has returned on the inclusive / exclusive comparison questions. Those that are inclusive ("Have you ever stolen anything from anyone?) result in increased accuracy - not a decrease. "Adjusting" the CQs should therefore result in a decrease in accuracy.

In the lab, in theory, every CQ should be too strong. After all they are real transgressions as opposed to the pretend "crime." And yet, we find that's not the case at all. Moreover, some programmed innocent fail. Does that mean asking if they stole the watch, cash, whatever, was too strong? We'd never say that is the case. Why then would we presume the CQs are too strong?

It's our job to run the test as we know. We introduce some good RQs and some good CQS and then we conduct the test. Let the chips fall where they may, with no unnecessary changes in the process.

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Ted Todd
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posted 02-19-2013 07:11 PM     Click Here to See the Profile for Ted Todd     Edit/Delete Message
Bill,

Backster never taught us to "weaken" the controls. The "remedy" was to adjust the time bars and leave the wording of the controls alone.

Ted

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Bill2E
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posted 02-20-2013 09:43 AM     Click Here to See the Profile for Bill2E   Click Here to Email Bill2E     Edit/Delete Message
Ted

Backster has changed slightly since 1985 in his teaching because of research. He had the Either/Or rule at one time, and changed to Some and More later regarding reactions on control vs relevant issue questions. The Either/Or rule produced to many inconclusive and incorrect DI calls.

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Ted Todd
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posted 02-23-2013 05:25 PM     Click Here to See the Profile for Ted Todd     Edit/Delete Message
Bill,

I went through Backster's in 1999. The Either Or and Some and More rules were still being taught. And who could ever forget having to spin the wheel, stand up in front of the class and recite the redemy for correcting "deficient comparrison questions"?

“Presence of reaction in the green zone and a lack of reaction in the red zone indicates truthfulness toward the relevant questions. Remedy-None. The comparison questions are functioning properly as designed”.
Ted

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Bill2E
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posted 02-23-2013 07:32 PM     Click Here to See the Profile for Bill2E   Click Here to Email Bill2E     Edit/Delete Message
And the portion "When you have reaction to the control and relevant, the relevant is competing with the control"

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Ted Todd
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posted 02-23-2013 07:51 PM     Click Here to See the Profile for Ted Todd     Edit/Delete Message
Which is exactly why Backster says you score to the lesser response in the comparison question. Which is why we still have this on going drama between Backster and the Feds! YAAADAA YAAADAA

Ted

[This message has been edited by Ted Todd (edited 02-23-2013).]

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rnelson
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posted 02-24-2013 11:14 AM     Click Here to See the Profile for rnelson   Click Here to Email rnelson     Edit/Delete Message
I think a lot of people are going to be increasingly uncomfortable with the idea of stochastic polygraph, in which we continually adjust the test/stimuli to achieve the data or reactions we want.

Stochastic models are good when we have a single objective - like target shooting. Make some holes, adjust the sights, make some more holes, etc., and the process becomes more precise.

It is different when we have two categorical objectives to choose from. In this case adjusting the data one way or another requires that we know in advance which is the correct one, or requires that we permit ourselves to use our personal opinion to influence the result of the test.

It is our goal is to get people to produce truthful or deceptive scores - but it is not our goal or our role to decide in advance to push the scores one direction or another.

Scientific testing involves a simple process: present the stimulus, observe/measure/code the response, lather, rinse, repeat, aggregate the data together, compare the result to the normative data (i.e, cutscores) to determine to determine the level of significance.

Start tweaking on the data collection process and we are going to get a lot of attacks around the notion that we caused the result to come out the way they did.

There seems to be some action underway to impose some order or authority onto the forensic sciences. We can walk away and not play with them, or we can think through the advantages of learning to think carefully about the test in terms of standardized procedures - part of which means determining whether the stimulus should be changed or adjusted during the test administration.

http://www.nist.gov/oles/doj-nist-forensic-science021513.cfm

When the relevant and comparison questions produce equivalent reaction then we would be tempted to assume that the difference in reaction is not significant or that one of the questions is defective. Which one? conservative judgement might say to err on the side of caution and weaken the CQ so to avoid or reduce FN errors. Data tell us that most inconclusive results are actually truthful.

In reality, we cannot know whether the observed lack of difference in one chart means anything or nothing. We cannot determine the signficance of that untill we have all the data. So, adjusting the data requires introducing our human bias into the test. Conservative scientific approach is to collect all the data without changing the stimulus and then determine the level of significance of the result.

No doubt Backster is a genius and we'll use some of his ideas forever. Same with Reid. But if we want to end the drama, then why don't we study the data and then follow the evidence. Strong-side/weak-side/left-side discussions are answerable questions.

If anyone has an interest in helping with this, then please contact myself or Mark Handler. Could be interesting.

.02

r

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"Gentlemen, you can't fight in here. This is the war room."
--(Stanley Kubrick/Peter Sellers - Dr. Strangelove, 1964)

[This message has been edited by rnelson (edited 02-24-2013).]

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Bill2E
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posted 02-24-2013 03:19 PM     Click Here to See the Profile for Bill2E   Click Here to Email Bill2E     Edit/Delete Message
Ray

Maybe I have mis-stated what I was trying to say. To clarify, Backster, in 1985 taught that reaction to the relevant question indicated deception to that question, if there control question was showing reaction it was his opinion the control was competing with the relevant issue. This what was taught.

Since that time I have had other instruction from other professionals and don't hold to the Backster premise from 1985. I believe Cleve has even moved away from that hard stance. We were discussing "can comparisons be too strong". Comparisons can compete with the relevant questions when they are not properly formulated and we can get errors. It has everything to do with the manner in which the comparisons are formulated. (pre test)

I do see reaction to controls and relevant in the same examination. Occasionally I see only reaction to the control questions and none to relevant questions. I do not adjust my questions during the actual examination, I have been taught not to do that in many ongoing training seminars.

[This message has been edited by Bill2E (edited 02-24-2013).]

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rnelson
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posted 02-24-2013 04:20 PM     Click Here to See the Profile for rnelson   Click Here to Email rnelson     Edit/Delete Message
Thanks Bill,

That is super interesting.

I knew that Baster used to teach that there should be a reaction to either the RQ or the CQ and not both.

It seems the data data don't' support that. If you look at the Ansley survey of scores (Ansley & Krapohl, 1999) they showed it is not the presence or frequency of reaction that differentiates liars from truthtellers but the strength or magnitude of reaction.

Other research has concurred with this - and it goes back to John Reid who had the conscientious wisdom and independent thinking to tell us that we need CQs precisely because it is normal for truthful person to show some reaction to the RQs.


Do they teach a "Some and More" concept now?

r

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"Gentlemen, you can't fight in here. This is the war room."
--(Stanley Kubrick/Peter Sellers - Dr. Strangelove, 1964)


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Bill2E
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posted 02-24-2013 04:34 PM     Click Here to See the Profile for Bill2E   Click Here to Email Bill2E     Edit/Delete Message
I have not been to the Backster School in some time. I believe he does teach Some and More now. The Either or Rule went out in the early 90's.

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Guyhesel
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posted 02-25-2013 09:39 AM     Click Here to See the Profile for Guyhesel   Click Here to Email Guyhesel     Edit/Delete Message
Hi Ray

I was interested in your comments on this. I agree that adjusting the "perceived" strength of a comparison question mid test can only be seen as prejudicial one way or another, I imagine being asked the reason why I dampened down a CQ ? but I can't think of an answer that could not be interpreted as I was trying to Bias the result in some way.

On another point In your comments you said that "Data tell us that most inconclusive results are actually truthful." is there any specific research to back this up! I think it's something a lot of examiners would agree with from a theoretical stance but I would be interested to see it tested.

Regards
Guy H

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skipwebb
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posted 02-25-2013 02:38 PM     Click Here to See the Profile for skipwebb   Click Here to Email skipwebb     Edit/Delete Message
This discussion begs the question of why NCCA teaches to move the "strongest" comparison beside the "strongest" relevant on each subsequent test after reviewing the prior test chart.

This makes no sense to me if we are to conduct an unbiased examination. I arbitrarily rotate the comparison questions on each chart so that each is compared to each relevant over the course of the examination. It seems this is much easier to support when questioned than the idea of evaluating test chart 1 and trying to adjust test chart 2 and then adjusting test chart 3 based upon the results of the prior chart. This rarely actually works in "real life polygraph". When I move the "strongest comparison" on a subsequent chart, it almost never is the strongest comparison on that subsequent chart. This opens up the argument that one is manipulating the test results in my opinion.

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Barry C
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posted 02-25-2013 06:03 PM     Click Here to See the Profile for Barry C   Click Here to Email Barry C     Edit/Delete Message
Skip,

That's not arbitrary (what you are doing). It's really a form of counterbalancing, which is a generally desired.

Usually you would see it in a study in which half the subjects are exposed to test A before test B and the other half, test B before test A to make sure there is no order effect taking place.

Guy,

Most of the validity studies we have show we're better at identifying the deceptive than we are the truthful. Don Krapohl developed the Evidentiary Scoring Rules as a means of balancing errors between FPs and FNs. Take at look at those two studies (2005 and 2006 APA Journal) for a good example of what you are looking for.

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rnelson
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posted 02-25-2013 06:13 PM     Click Here to See the Profile for rnelson   Click Here to Email rnelson     Edit/Delete Message
You can also look at Appendix B in the meta-analysis.

It shows the inclusives for the 45 included surveys and experiments.

Unweighted mean of all guilty-inconclusives was 10.0% and 13.7% for innocents.

It's blunt, but the trend is clear.

Maybe Barry can tell if the difference is signfificant. I'm away from home for another week, and my 'puter went up in smoke last week - so I'm reinstalling and recovering a lot of stuff onto a new machine and cannot do it right now.

.02

r

------------------
"Gentlemen, you can't fight in here. This is the war room."
--(Stanley Kubrick/Peter Sellers - Dr. Strangelove, 1964)


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Guyhesel
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posted 02-26-2013 03:16 AM     Click Here to See the Profile for Guyhesel   Click Here to Email Guyhesel     Edit/Delete Message
Barry / Ray
Thanks for your comments, will take a look.

Skip,
I agree with rotating the comparisons, Could this be one factor that helps the good validity
of the UTAH technique?

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skipwebb
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posted 02-26-2013 09:33 AM     Click Here to See the Profile for skipwebb   Click Here to Email skipwebb     Edit/Delete Message
I absolutely believe so. That and only comparing each relevant against the preceding comparison question.

I'm convinced "floating windows" in the pneumo tracings and strongest comparison moving against strongest relevant are both "water cooler" science created by bored instructors who discuss polygraph a great deal and run polygraph very little.

Neither procedure really adds anything of value to the process and I am unawaree of any science to support the rationale for doing either.

Using question onset to 15 seconds or 20 seconds for the pneumo and rotating comparisons on each test chart appears to work just fine and provides plenty of data upon which to make decisions without having to explain our rationale for what we do other than to say the school(s) teach it that way.

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rnelson
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posted 02-26-2013 10:07 AM     Click Here to See the Profile for rnelson   Click Here to Email rnelson     Edit/Delete Message
Skip,

Something interesting.

Mark and I have been studying the strong-side/weak-side/left-side/right-side.

There does seem to be a slight advantage to the strong side - in terms of test performance using corrected norms for each model. However the difference between the strong-side solution and left-side (preceeding) is so small it is actually meaningless and in all likelihood un-noticable except in occassional annecdotal cases. (and if you look at enough cases you can find something - but that ain't how science works).

So, there is rationale for the Utah solution (preceeding CQ) if the performance is virtually the same and the reliability/simplicity is actually better (less to argue about).

I think this fits with what you are describing.

.02

r

------------------
"Gentlemen, you can't fight in here. This is the war room."
--(Stanley Kubrick/Peter Sellers - Dr. Strangelove, 1964)


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Barry C
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posted 02-26-2013 11:40 AM     Click Here to See the Profile for Barry C   Click Here to Email Barry C     Edit/Delete Message
I imagine pairing the strongest CQ to the strongest RQ (from chart to chart) was a means of trying to counter the recognized bias against the truthful in many scoring systems. Maybe it was arbitrary, but it would seem that somebody recognized the truthful do not react to the CQs as strongly as the deceptive do the RQs and this was an attempt to remedy that issue. It's probably not optimal, and it ignores that some seemingly strong reactions could be random, meaning the pairing of two strong questions may not have the intended effect. I don't know how many people actually follow that rule, so I have no idea if the studies on the federal ZCT are an indication of its usefulness.

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Barry C
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posted 02-26-2013 12:24 PM     Click Here to See the Profile for Barry C   Click Here to Email Barry C     Edit/Delete Message
quote:
You can also look at Appendix B in the meta-analysis.
It shows the inclusives for the 45 included surveys and experiments.

Unweighted mean of all guilty-inconclusives was 10.0% and 13.7% for innocents.

It's blunt, but the trend is clear.


I use a continuity correction (because you can't divide by zero, and some studies have 0 INCs), so my numbers are a little different.

I calculated the average Truthful INCs and average Deceptive INCs for the single-issue tests only (including the outliers). (I did a meta-analysis of the reported results in the APA meta-analysis using the number of truthful and deceptive cases, respectively and the number of truthful INCs and deceptive INCs, respectively.) They are different:

Truthful
Average 15.7% (95% CI = 14.6% to 16.9%)

Deceptive:
Average 11.6% (95% CI = 10.7% to 12.6%)

If there were no difference, the confidence intervals would overlap, and you'll notice they don't. So, on average, INCs are more likely to be truthful than deceptive, but it's not a huge difference.

The bottom line is that the INC zone, if you will, protects us from erroneous decisions when a score is (essentially) equally probable for a deceptive or truthful examinee. (It's a good idea.)

[This message has been edited by Barry C (edited 02-26-2013).]

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rnelson
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posted 02-28-2013 09:44 AM     Click Here to See the Profile for rnelson   Click Here to Email rnelson     Edit/Delete Message
Barry,

It is not quite correct to interpret inconclusive as essentially equally probable for deception or truthtelling. The error statistics for the two categories are unlikely to be exactly the same, and we could actually calculate an odds ratio - and perhaps even conditional probabilities based on these, that the examinee actually belongs to one group or another.

It brings us back to the arbitrariness of hypothesis and significance testing versus the interpretation of p-values and standard errors - but there is always value in rules because they create more consistent and reliable interpretations.

Inconclusive simply means that the numerical scores are not signficant.

.02

r

------------------
"Gentlemen, you can't fight in here. This is the war room."
--(Stanley Kubrick/Peter Sellers - Dr. Strangelove, 1964)


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Barry C
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posted 02-28-2013 12:31 PM     Click Here to See the Profile for Barry C   Click Here to Email Barry C     Edit/Delete Message
Sure, that's true if you're talking about a single score (with an arbitrary level of significance selected). I was talking about the inconclusive "zone" in general. If you have a scoring system with symmetrical distributions and the cut-score is in the center of where the two overlap, then the areas on each side (of the cut-score) are equal. That was what I meant. You don't need to understand any math to look at where the distributions overlap and know that's the more dangerous area to place your bet. (Of course, you have to pretend the tails don't keep going in order to decide where to end the overlapping areas.)

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