Friday, August 19, 2011

The Reliability and Admissibility of Lie Detector (Polygraph) Test

By: Melvin R. Royo

Lie Detector (Polygraph) Test has been widely used for a long time by CIA, FBI, Law Enforcement, Secret Service and best managed companies for pre-employment screening, periodic audit and specific case investigation. It is also recognized as a valuable tool for decision-making and an effective scientific investigative tool to solve various cases all over the world.

In the Philippines, lie detector is also being used by progressive companies and law enforcement agencies like Philippine National Police and National Bureau of Investigation. However, many people are still unconvinced using it. They still ask “Is lie detector test reliable? Is it admissible in court?”

The reliability and accuracy of the test depends on the examiner, examinee and the system. The Examiner and Examinee play vital role on the reliability and accuracy of the results. Establishing a good rapport between the two is a very essential thing to be considered to have a concrete result. Just like the doctor and a patient: if either does not cooperate or play his own role, the patient’s complaint cannot be adequately treated. The examiner and the examinee should play their respective roles the best way they can. They should be both physically and mentally stable. The examinee must also cooperate and obey the instructions given by the examiner.

The examiner must project impartiality and carefully explain the purpose of the test. It is also very important that he should not stray or be lost into question areas not generally relevant to the purpose of the test or case.

And most of all, the examiner must adhere strictly to the code of ethics set by American Society for Testing Materials (ASTM), the world’s oldest developer of industry standard. These standards include:

a. The Examiner must be a college graduate, has a good moral character, training on polygraphy (including psychology and physiology) and scientific interrogation.
b. The Instrument must record at least three (3) systems of the human body: Respiratory (breathing) tracing, Electrodermal (sweating) tracing and Cardiovascular (blood pressure, blood volume and pulse beat) tracing.
c. The examination must be asked with exclusive control questions, done with acquaintance/ stimulation test and at least three comparison question technique (control and relevant question) charts.
d. Results will be released based on the numerical scoring.

On the other hand, the examinee must have taken a rest with at least four to five hours sleep before taking the test. He/She should not be drunk or has not taken any prohibited drugs or medication because it will suppress the normal activity of the Central Nervous System. It is also very essential that the examinee must be free from any physical and mental abuse prior to the test. The examinee, who is pregnant of 8-9 months, is also discouraged from taking the test; and a parental consent is needed for minor examinee.

The accuracy and reliability of lie detector test is still being questioned. Many people still do not know that the lie detector test has been proven to be accurate like the Treasury Department funded experiments that showed polygraph to be 90% accurate. In more recent research, the confirmed average validity was shown to be 96%. Only 4 to 10% of the results were declared inconclusive and almost no error.

In the Unites States, most states allow the use of polygraph test results as evidence provided that both parties have agreed to their admissibility prior to the examination under the terms of conditions. On the other hand, in one US state, New Mexico, polygraph evidence is admitted in the same way as other scientific evidence.

Although lie detector test has been used in the United States and in the Asia Pacific Region for a long time, there is still no court ruling on the admissibility of polygraph evidence in any court proceedings in these countries. It will only become admissible if ruled on by the judge. However, in Japan, polygraph evidence is admissible in court.

There are few cases in the U.S. that lie detector test was considered to be admissible. The U.S. Court of Appeals declared in precedent setting decision that “the Science of Polygraph has progressed to a level of acceptance sufficient to allow the use of polygraph evidence” on the case of U.S. vs. Piccionnona in 1989. Same also with the case of William Daubert vs. Merrel Dow Pharmaceuticals, Inc., in U.S. Supreme court sometime in 1993, in which the court adopted polygraph expert scientific testimony in federal trial. Another example is about the U.S. vs. Scheffer trial in 1998, in which the polygraph (lie detector) provides another accurate form of circumstantial evidence of consciousness of guilt and found it sufficiently reliable to be admitted.

The public’s general opinion is that the lie detector is not allowed in court proceedings under any circumstances. The fact is that the lie detector result is admissible in most courts in the US. The Supreme Court has yet to rule on the issue of admissibility so it has been up to individual jurisdictions to allow or disallow them. There are some jurisdictions that have absolute bans on admitting polygraph results, but most allow them. The judge as well is least likely to use lie detector test if it was administered by an unaccredited examiner. The simple fact is that both the plaintiff and the defendant have to agree to having the results of the test be admissible, prior to the examination being conducted. Since the results of the test are going to hurt one party and help the other, the likelihood that both parties will agree to admissibility before knowing how it will affect their case, is minimal. Because of this, results of Polygraph testing are rarely admitted as evidence

In the Philippines, polygraph evidence was first discussed by the Supreme Court in 1978 in People v. Daniel (G.R. No. L-40330 Nov. 20, 1978). In this case, the accused submitted to the trial court the results of a polygraph test to show that he was innocent of the crime of rape. After almost 12 years, the Supreme Court was confronted again with polygraph evidence in People v. Adoviso, 309 SCRA 1 (1999). Pablo Adoviso was convicted of two counts of murder by the Regional Trial Court of Camarines Sur. He was identified by two witnesses as the perpetrator of the crimes. Among the evidence offered was the testimony of a polygraph examiner of the National Bureau of Investigation (NBI) who conducted a polygraph test on Adoviso. The polygraph examiner opined that Adoviso’s polygrams revealed that there were no specific reactions indicative of deception to pertinent questions relevant to the investigation of the crimes. Despite this finding, the trial court found Adoviso guilty beyond reasonable doubt.

In the report on the issue of the mysterious theft of a service vehicle in Camp Crame, the Philippine National Police (PNP) will be giving lie detector test to 40 PNP personnel to determine the circumstances about the incidents. Reports say that the PNP Criminal Laboratory will process the results that are known to be “unreliable and ordinarily not accepted as evidence in criminal trials.” (Phil. Daily Inquirer, August 11, 2011 issue)


The use of lie detector test on this probe will be very much helpful in determining the people behind the incident. The credibility of the result, however, might be jeopardized since the investigation will be conducted within the jurisdiction. There might have a bias or delay in the releasing of the result to prolong the investigation. Hence, a third party private and reputable lie detector company would be a great choice.

Truth Verifier Systems, Inc. (TVSI) is the first and the Number 1 industrial lie detector company in the Philippines. It has four fully computerized lie detector (polygraph) instruments. Its President, Capt. Conrado G. Dumlao, decided to open such business to address the needs of the security industry to combat the growing fraud activities as well as to strengthen the pre-employment screening. Capt. Dumlao is listed as an active Professional Polygraph Examiner and International Liaison Committee Member of the American Polygraph Association, U.S.A.

TVSI was awarded by the Philippine National Police as Hall of Fame for being the most consistent recipient of Best Private Detective Agency Award. Its professional and skilled examiners also cope with the changes by continuous trainings and workshops. Established in the Philippines in 1966, it is now 45 years in quality service. It is the first ISO 9001:2008 Certified Company for lie detector testing, detective and investigative services, and training. It has also been recognized for its exemplary service, expertise, integrity and truthful reporting by numerous local associations making it also known globally.

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