The Last Word: A Critique of Krapohl's Closing Comments on Validated Polygraph Techniques

by James Allan Matte


The intellectual debate that began with the publication of Donald Krapohl’s “Validated Polygraph Techniques” in Polygraph, Volume 35, Number 3, 2006 of the American Polygraph Association, resulted in responses from Cleve Backster, Director of the Backster School of Lie Detection, San Diego, CA, Nathan J. Gordon, Director of the Academy for Scientific Investigative Training, and James Allan Matte, President of Matte Polygraph Service, Inc., all of which were published in Polygraph, Volume 36, Number 1, 2007. In that same issue of Polygraph, Krapohl authored a “Rejoinder to Criticisms by Messrs Backster, Gordon and Matte” which was countered by a “Reply to Krapohl’s Rejoinder to Criticism of his Article on Validated Polygraph Techniques” by Matte. However, Krapohl was afforded the final commentary by publishing his “Rejoinder to Criticisms by Matte: Closing Comments” which would have been acceptable if the contents of Krapohl’s closing comments had fully and accurately addressed the issues raised in the debate. Sadly, it did not. Therefore this author (Matte) felt compelled to submit to the Editor of Polygraph a “Critique of Krapohl’s Closing Comments” which was initially accepted for publication with the advisory that Krapohl would be given a copy of Matte’s critique for his reply, both of which would be published in the next issue of Polygraph. This author (Matte) was subsequently notified by the Editor that his “Critique of Krapohl’s Closing Comments” would not be published, which leaves the accuracy and relevancy of Krapohl’s closing comments unchallenged. Therefore, in order to correct the record and finally put this intellectual debate to rest, the suppressed article titled “Critique of Krapohl’s Final Comments” is published herein for dissemination to those interested in this debate and the scientific aspects of polygraph in general.

The Last Word

In his closing comments, Donald Krapohl maintains his stance on validated polygraph techniques (Krapohl, 2006) and continues to argue for the exclusion of Nate Gordon’s Integrated Zone Comparison Technique and Backster’s Zone Comparison Technique from his list of validated polygraph techniques while retaining the MGQT as a validated technique in spite of its poor accuracy (25%) in the identification of the truthful examinee. He further attempts to justify the acceptance of a low accuracy rate for truthful examinees in non-judicial cases conducted by government, law enforcement and PCSOT examiners who conduct multiple-issue polygraph examinations, stating that “no multiple-issue format is likely to be able to achieve 90% accuracy for truthful examinees without missing a significant percentage of liars.” He also continues to justify the use of studies based solely on the blind scoring of charts as validity studies in spite of the fact that it fails to yield the true accuracy and error rate. In this critique I will show that in his closing comments, Krapohl uses examples to support his arguments that fail to recognize and address the main thrust of my position on validated polygraph techniques which among other things require equal validity for both the truthful and deceptive examinees, which can be attained with the use of current polygraph techniques.

The field study by Gordon, Fleisher, Morsie, Habib, and Salah (2000) confirmed 288 cases by confession and 21 (7.29%) by judicial conviction. It should be noted that the judicial convictions were used to confirm deceptive (DI) cases only. Krapohl’s 11th requirement for validation necessitates only 10 DI and 10 NDI cases confirmed by confession as the only means of establishing ground truth. I would argue that 288 confirmed cases by confession more than adequately meets Krapohl’s 11th requirement as well as those from peer-reviewed journals. Yet Krapohl ignores this most obvious argument for the inclusion of the Integrated ZCT in the list of validated polygraph techniques, and submits a 2X2 matrix to show that judicial convictions can only be used to confirm DI (Guilty) cases, not NDI (Not Guilty) cases. However he fails to mention that confirmation by confession would suffer the same fate under his 2X2 matrix formula with the same faulty results. A confession from a guilty examinee can be used to confirm examinee(s) found truthful on the same issue within the same case, and likewise a guilty verdict can be used in the same manner under the same circumstance, inasmuch as it has been shown (Huff, Rattner & Sagarin, 1986) that the rate of wrongful convictions is 0.5 percent but the rate of false confessions is as yet unknown, although its error rate is expected to be comparatively low under polygraph test conditions where a non-accusatory approach is mandatory. Krapohl’s consistent argument for the exclusion of judicial convictions as ground truth in field validation studies and Gordon’s Integrated ZCT as a validated polygraph technique is undoubtedly without merit.

In reference to my critique of Krapohl’s criteria he used to select cases for his Validated Polygraph Techniques article, Krapohl admits that an exhaustive sample as I had suggested was better than a random sampling of field cases in that “it would give better resolution on a number of factors that (random) sampling may miss.” However he states that “Random sampling may be adequate alternative so long as standard scientific practices are put into place.” The Daubert standard (William Daubert v. Dow Pharmaceuticals, Inc., 113 S.Ct 2786, 125 L.E.2d 469, 509 U.S. 1993) for the admissibility of polygraph tests in court require among other things that its potential error rate be determined. The true error rate can only be known when all of the examinations for a particular period are considered and factored into the data base. Errors in chart interpretation by blind scorers regardless of its random sampling reveal only the degree of reliability that can be placed on that method of chart interpretation and the competency of the blind scorers. The excuse that exhaustive sampling can be costly in time and effort has not hindered those of us in private practice who have conducted such field studies at our own expense.

Krapohl’s inclusion of the Horvath (1977) field research study to validate the Reid Technique in spite of the fact that the study stated “All polygraph records were taken from examinations conducted by field-trained examiners according to a standard control-question technique (Reid & Inbau, 1966) into which the variations advocated by Arther, (1969b) had been incorporated” which implied that the Arther Technique had been used. Nevertheless, Krapohl rejected that assumption, stating that “The Arther (1969b) citation in the above quotation referred to an article titled Irrelevant Questions. As the title might suggest, the content of the Arther article was on the construction of irrelevant questions. In other words, in the Horvath (1977) research the Reid Technique had been followed but it included Arther’s recommendations on irrelevant questions.”

However, Dr. Horvath (2007a) provided this author with the test format used in his study which coincided with the Arther format rather than the Reid Format. Furthermore, Dr. Horvath (2007b) stated that “the examiners in my study had been trained at the Arther school.” It was well-known during that period (1977) that graduates of Arther’s National Training Center of Lie Detection would not dare use a polygraph technique other than the Arther technique for fear that Richard O. Arther would not support their findings if their test results were challenged.1 Therefore, considering the statement made in Horvath’s study regarding the method used, the fact that the format matches the Arther Technique, and the examiners in that study were all graduates of Dick Arther’s polygraph school, can only lead to the conclusion that the Arther Technique, a derivative of the Reid Technique was used in Horvath’s study. As the old saying goes, “If it looks like a duck, walks like a duck and quacks like a duck, then it must be a duck.”

Therefore, if Krapohl can use a derivative technique such as the Arther Technique to validate the Reid Technique, then the Backster Technique should be able to use validity studies from derivative techniques such as the Federal ZCT, the Quadri-Track ZCT, the Integrated ZCT, and the Utah ZCT, to validate the Backster Zone Comparison Technique.

Krapohl states that “field research is plagued by an intractable problem of its own, the difficulty in obtaining ground truth in all cases. As was pointed out by the National Research Council (2003), field research tends to inflate estimates of polygraph accuracy because confirmation is more likely to come when the polygraph decision was correct. Unless confirmation is secured for 100% of an exhaustive sample of field cases, those data will always be suspect. For example, if 500 cases were conducted, but only 200 had confirmation, and the polygraph led to the confirmations (typically confessions), those 200 cases may be different in some qualitative way from the rest of the 500-case sample.”

The answer to that, as I had mentioned in my previous reply, is to determine the reactivity or physiological responsiveness of both the confirmed and unconfirmed cases by acquiring the average scores per chart for each case for comparison which would show whether those confirmed cases produced significantly greater reactions and consistency of response then examinees in the unconfirmed cases and whether the inconclusive rate was significantly different. However I would like to point out that the National Research Council’s 2003 report indicated that field research estimates of polygraph accuracy were somewhat inflated not so much by the manner of data acquisition as the effect of physical and mental countermeasures by the guilty which would increase the false negative rate and the fear of error by the innocent which would increase the false positive rate. However, the National Research Council failed to recognize the fact that examinees in field cases have the opportunity to employ countermeasures and indeed do employ them, hence the reported results of field studies embody the effects of countermeasures. As to false positives caused by the innocent examinee’s fear of error, that issue has been adequately addressed with the use of the Quadri-Track Zone Comparison Technique which has been in use by several agencies for several years and has been subjected to a field research study (Matte & Reuss, 1989) which was accepted by the National Research Council as one of only seven field studies that met their scientific criteria. An independent replicate field study is currently being completed on the Quadri-Track ZCT.

However, the issue in Krapohl’s closing comment that disturbed me the most was his adamant retention of the MGQT as a validated technique in spite of the fact that it was only 25 percent accurate in the identification of the truthful examinee. The fact that the MGQT correctly identified 97 percent of the deceptive examinees surely had an impact in Krapohl’s decision to include it in his list of validated techniques, which clearly reflects an individual who is prosecution oriented. His outright rejection in requiring that field research provide a minimum of 90 percent accuracy in the identification of the truthful as well as the deceptive examinee except in judicial cases, shows a lack of empathy for the innocent examinee who may suffer the consequence of lost employment and career, the agony and expense of a trial, and possible conviction, none of which necessarily start out as judicial cases. For instance, an examinee who fails his Post Conviction Sex Offender Test can be reincarcerated. An innocent examinee who fails a polygraph test conducted by the police can result in his being charged and tried. Finally, in an actual case, an individual who had been arrested for selling illegal drugs was given a choice of 30 years in prison which would be reduced to 10 years if he cooperated with the police and provided them with a statement that listed the identity of all the drug pushers he knew and had been involved in his career as a drug peddler. The individual consented and after issuing a written statement he was polygraphed by an examiner who used a multiple-issue test which found him deceptive resulting in his incarceration for 30 years. Nine years later, his parents hired an attorney who caused a quality control review of his polygraph test which revealed that the examiner had used a technique that employed six relevant questions and one control (comparison) question. The judge concluded that the test was invalid. Such a miscarriage of justice would most likely not have occurred if a polygraph technique that enjoyed a minimum 90 percent accuracy in the identification of both the truthful and deceptive subject had been used. Krapohl stated in his closing comment that “Because no multiple-issue format is likely to be able to achieve 90% accuracy for truthful examinees without missing a significant percentage of liars, examiners may find that they must accept a higher false positive rate in some settings.”

On the contrary, those who use multiple-issue formats, whether in government agencies, law enforcement agencies or the private sector, need not compromise their standards and sacrifice the innocent in order to identify the guilty. For the past 25 years, I have lectured regarding the use of the specific single-issue zone comparison technique to resolve multiple issues by addressing each issue separately in single-issue tests, i.e. test A, test B, test C. When multiple-issue tests such as employee screenings or pre-employment tests are conducted and the examinee produces a significant unresolved response to a relevant question on two or more charts, the results are classified as inconclusive and the examinee is rescheduled for another test wherein the unresolved question is inserted into a single-issue zone comparison test that enjoys a minimum 90 percent accuracy. This method of testing is known as the successive hurdle approach. Multiple-issue tests can be used to clear an examinee who consistently responds to certain disguised control questions and not to any of the relevant test questions. However, the standard should require that a decision of deception can only be rendered with the use of a single-issue zone comparison test that has been validated with a minimum 90% accuracy in the identification of the deceptive and truthful examinee. This successive hurdle approach addresses and nullifies complaints by polygraph opponents who wish to ban the use of pre-employment and other screening type polygraph tests due to their excessive potential for false positives. Several law enforcement agencies and private polygraphists have reported to me over the years of their success in the use of this approach.

The American Polygraph Association must make every effort to protect the innocent with polygraph procedures that will ensure their correct identification. Research standards and technique validation should not be left to the discretion of one individual but to a committee comprising representatives of government, law enforcement and lastly but not least the private sector which has historically contributed the major advances in the polygraph profession.


  • Arther, R. OI. (1969). Irrelevant questions. Journal of Polygraph Studies, 3(6), 3-4, (b).
  • Gordon, N. J., Fleisher, W. L., Morsie, H., Habib, W., & Salah, K. (2000). A field validity study of the Integrated Zone Comparison Technique. Polygraph, 29(34), 220-225.
  • Horvath, F. S. (1977). The effect of selected variables on interpretation of polygraph records. Journal of Applied Psychology, 62(2), 127-136.
  • Horvath, F. S. (2007a). Communication by e-mail with J.A. Matte, regarding test format used in his 1977 study.
  • Horvath. F. S. (2007b). Communication by e-mail with J.A. Matte, regarding Arther trained examiners in his 1977 study.
  • Huff, C. R., Rattner, A., & Sagarin, E. (1986). Guilty until proved innocent: Wrongful conviction and public policy. Crime & delinquency, 35(4), 518-544.
  • Krapohl, D. J. (2006). Validated polygraph techniques. Polygraph, 35(3), 149-155.
  • Krapohl, D. J. (2007). Rejoinder to criticisms by Matte: Closing Comments. Polygraph, 36(1), 50-56.
  • Matte, J. A. (2007). A reply to Kkrapohl’s rejoinder to criticism of his article on validated polygraph techniques. Polygraph, 36(1), 45-50.
  • Matte, J. A., Reuss, R. M. (1989). A field validation study of the Quadri-Zone Comparison Technique. Polygraph, 18(4), 187-202.
  • National Research Council (2003). The Polygraph and Lie Detection. Committee to Review the Scientific Evidence on the Polygraph. Division of Behavioral and Social Sciences and Education. Washington, DC: The National Academies Press.
  • Reid, J. E., & Inbau, F. E. (1966). Truth and Deception: The polygraph (“lie-detector”) technique. Williams & Wilkins: Baltimore, MD.

1As Chief of Polygraph Division for Hammer Security Service, Inc. in Buffalo, NY in the 1970’s this author supervised several Arther Trained polygraph examiners during their internship for certification. This author, a Backster graduate, was required by the corporate president who was a guest lecturer at NTC to attend Arther seminars for training in the Arther technique.