posted 01-07-2012 10:50 AM         

AFTER YOU CAUGHT UP WITH JOHN IN THE PARKING LOT, DID YOU SEE
MARK BEFORE YOU HIT JOHN?

DID JOHN TURN TOWARD YOU AND MOVE HIS FIST TOWARD YOU BEFORE
YOU HIT HIM?

JUST BEFORE YOU HIT JOHN, WAS HE TURNING TOWARD YOU AND
MOVING HIS FIST TOWARD YOU?

posted 01-07-2012 06:10 PM            

The first question takes the listener/examinee in three directions 1) after you caught up with John, 2) did you see Mark, 3) before you hit John?

Assumes he hit John - is this in question? If it is questioned whether he hit John, then this questions would seem to assume guilt (he hit John). If it is known that he hit John, then this is less troublesome but the question is still cognitively chunky.

The other three questions make reference to the behavior of someone other than the examinee: 1) did John turn toward you... 2) was he turning..., 3) did John's behavior...

Where is the science in attaching polygraph sensors to one person's body to test the behavior of a person who is not in the room?

This may work if the polygraph actually measures lies per se. But it seems the evidence on polygraph validity suggests that this may not be the case.

You can call me simple-minded, but I prefer some version the basic "did you do it" where "it" describes the examinee's behavior.

r

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

posted 01-08-2012 05:04 PM            

I agree with Nelson there are "questionable featuers" (sp)as the questions are compound/complex. For this reason I'm not comfortable with most of them. It appears the questions are geared to a self-defense issue not addressed in the case facts.

Based on my understanding of the facts I don't care for the word "see" in Q1. I'm presuming "Mark" you ID in the initial post is the deputy. Hall (defendant) caught up with Pobanz (victim) in the parking lot, hit him in the head and Pobanz died. Hall & brother-in-law denied speaking with the (guard) and denied being aware the deputy was present until (after) Pobanz was struck. Is this question an attempt to verify Hall was not aware of a police presence until (after) Pobanz was struck? While Hall may not have seen the deputy since the deputy was behind him (at least during the foot pursuit), would it not have been better to ask if the commands shouted by the deputy were heard by Hall?

I prefer more direct questions and would consider the following based on case facts. I would likely change/add terminology and questions based on the pre-test interview or new information:

1. Did you hear anyone holler for you to stop chasing Poblanz?

2. The primary relevant issue. Did you hit Poblanz in the head (without a justifiable reason)? Pre-test to the guard reporting Poblanz was simply gesturing a specific direction with an open hand (not fist)when struck by Hall. Unless there is missing information, no indication Poblanz swung at Hall or was aggressive towards Hall. Ensure during pre-test Hall is aware he did not hit Poblanz with the rock.

3. Did you lie when you said you believed Hall was trying to strike you?

4. DY lie when you said you hit Pobanz in self-defense? This may not be good at all as I'm presuming Hall has reported he took Pobanz' hand gesture while speaking to the guard as an attempt to strike him.

END.....

posted 01-10-2012 11:31 AM            

without knowing the case facts; which I believe are immaterial, this appears to be a classic case of trying to cover every possible aspect of a crime through a polygraph examination. I thought we, as a community, had grown out of that, but I guess not.

K.I.S.S.

posted 01-11-2012 12:46 AM            

after having been around a couple of days I have found that many examiners who are not either supervised, quality controlled or working without benefit of peer discussions enter into a world of "I must know what I'm doing because I've been doing it a long time" syndrome. Short cuts are taken, ego's expanded and resume's built through shoddy work, unexposed poor performance and a LOT of luck in not being sued or exposed as a "chartroller."

You mentioned the score was +19, but you didn't mention how many charts, 3 or 7 position scoring, was a proper QC conducted and was a recognized technique employed?

Just curious,

Jim

posted 01-11-2012 11:23 AM         

Here is an online link to the report: http://justiceforerik.org/Hall%20Polygraph%20report%20Dr.%20David%20Raskin%20040207%20_0402195018_001.pdf

posted 01-12-2012 10:50 AM            

If it is Dr. Raskin's test, then it is a Utah MGQT (4-question), with three charts (though possibly 5), scored with the Utah 7-position model, and interpreted with the Utah MGQT decision rules.

Utah 4-question exams are multi-facet event-specific exams.

Most polygraph examiners are taught to interpret the results of multi-facet exams as if the criterion variance of the RQs is independent (i.e., whatever external facts/cercumstances/behavior cause the examinee to be deceptive or truthful to one question may not affect the other questions.)

These questions fit the multi-facet hypothesis: 1) did you see mark, 2) did john turn, 3) was he turning and moving his fist toward you, and 4) did john's bx make you beleive...

However, the scientific literature has not supported the hypothesis that multi-facet event-specific questions are independent. Instead the scientific evidence indicates that multi-facet exams are more accurate when interpreted with decision rules that assume the criterion variance of the RQs to be non-independent.

For this reason, Utah exams - as used by Utah scientists - use the grand total decision rule with the Utah ZCT (even when using multi-facet RQs.

Utah MGQT (multi-facet event-specific) decision rules are as follows:

1) Grand Total >= +6 = NDI if all subtotal scores are + (ignoring zeroes)
2) Grand Total <= -6 = DI if all subtotal scores are - (ignoring zeroes)
3)If the subtotal scores are mixed + and - values then use the Spot Score Rule in which
3a) Subtotal Scores >= +3 = NDI
3b) Subtotal Scores <= -3 = DI

Because the scientific evidence does not support the polygraph as capable of determining truthtelling and deception within a single examination: split calls are not permitted. Therefore, a deceptive result to any questions negates the possibility of a truthful result to other questions - which are then reported as INC if not deceptive.

Test results are reported at the level of the test as a whole.

These are complicated rules. But, if you pay attention to the scientific evidence, and the logic of the rules - they are actually correct.

The advantage of these rules is that they will give good accurate results - assuming the target issues questions are viable and properly formulated (they are questionsable for this exam).

Most examiners will simply use the SSR for all MGQT (multi-facet and multi-issue) exams - and assume independence (even though the evidence does not support this hypothesis for multi-facet exams).

The effect of these Utah MGQT rules is to better manage the deflation of alpha on the truthful side - which results in weak test specificity with the SSR when using traditional uncorrected cutscores.

While the Utah folks corrected the problem procedurally, the ESS overcomes this problem for MGQT (multi-facet and multi-issue exams - for which we continue to impose the assumption of criterion independence) by selecting a Sidak (statistically) corrected cutscore according to the number of RQs. This will achieve the same effect, but permits the use of the simpler SSR instead of the complex Utah MGQT decision rules.

Peace,

r

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

posted 01-12-2012 11:25 PM            

Jim

posted 01-13-2012 07:05 AM            

That's what they mean when they say "all positive, ignoring scores of zero."

Again, there is no published research on this technique.

However, Honts told me that he and Raskin had completed studies on this technique but they were not published.

What they seem to have known is that there is a proportion of truthful persons who will produced non-positive subtotal scores in the context of several event-specific test questions.

Because the test is imperfect, with accuracy presumably averaging somewhere over 90%, there is always the possibility of error - the possibility that a truthful persons produces a sufficiently negative grand-total or sub-total score to merit a deceptive test result. That possibility seems to be a little less than 10%.

There is also the possibility (among other possibilities) that a truthful person will produce an inconclusive score. If we employ subtotal requirements in the decision rule for truthful (and inconclusive results), then we are actually allowing sub-total scores (which are less accurate than grand-total score) to control inconclusive results. In fact, because there are more sub-totals than grand-totals (duh!) and because the probability of inconclusive accumulates with the number of questions/decisions, the sub-totals actually do more to mediate inconclusive results than does the grand total.

Senter (2003) showed that two-stage rules can increase the accuracy of MGQT multi-facet exams compared to the spot-score-rules. The meaning of this - consistent with earlier studies on the mgqt - is that there is no support for the hypothesis that the criterion variance of multi-facet questions is actually independent. Instead the evidence, in 1989, 1993 and 2003, seems to suggest the opposite - that the criterion variance of multi-facet investigative questions, regarding a single known or alleged incident, is non-independent.

Mark and I studied the data we have regarding single-issue Federal ZCT exams - for which people argue different opinions about whether it is a single issue or multi-facet exams.

The correct question and argument is not whether the exam is single-issue or multi-facet, but whether the criterion variance (whatevever are the external facts/circumstances/behaviors that cause a person to be deceptive or truthful to each individual question) will or will not affect the criterion state of the other questions.

Questions are independent only if those external facts/behaviors/circumstances affect only individual questions and DO NOT affect other questions.

What matters most here is not someone's opinion but the answer that the evidence gives us. There are many situations in many different fields when opinion and evidence disagree - in which case one of them must be up-graded. (Hint: it's not OK to change the evidence, and it's also not OK to ignore the evidence.)

In looking at nearly 30 different samples (not 30 cases, 30 samples of cases) of Federal ZCT exams we found that more than 1/2 (>50%) of truthful persons produced a non-positive (zero or lower) sub-total score.

So, it is no surprise that the two-stage rules described by Senter & Dollins have become important. These rules place primary emphasis on the grand-total (big number), and secondary emphasis on the sub-totals (small numbers).

Is it beleivable that more than 1/2 of truthful people may not pass a polygraph? We think so - under some circumstances. Look back at the most recently published Federal study that made use of Federal ZCT decision rules. Blackwell (1999) reported test specificity to truthtelling at rates that were less than chance. Studies since then have consistently shown that improved decision rules (two-stage) can improve overall test accuracy.

Still, Federal rules have their place of usefulness if you want to be exceedingly cautious and do not care about clearing the truthful person.

Anyway, Raskin and the Utah folks probably found similar evidence, and seem to have formulated rules that effectively manage the complex variance of multi-facet exams of known events. For ZCT exams the Utah folks simply use the grand-total decision rules - which avoids the problem altogether. (BTW, the grand-total rule consistently gives the highest level of test accuracy for nearly all techniques.)

All of this is the reason I say that the Utah MGQT decision rules, although somewhat complex, are actually correctly formulated.

With the ESS, these complexities are managed through the use of Bonferonni correct alpha cutscores (and two-stage rules) for results based on sub-total scores of ZCT exams, and through the use of Sidak corrected cutscores for truthful results when using the spot-score rule. This achieves the same results using procedures that are simpler and more intuitive for field examiners.

'mornin ya'll

r

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