AAPP Standards and Principles

Statement of Principles

The AAPP holds that the difference between truth and deception is as fundamental as the difference between right and wrong, and that the well-being and needs of communities, agencies, and individuals are best served by an objective and scientific approach to lie detection and credibility assessment. Polygraph testing, forensic psychophysiology, and credibility assessment, are evolving fields of science, intended to be used as decision support tools. These tools should aid investigators and referring agencies in making decisions about the truthfulness or deception of individuals in diagnostic and screening test circumstances. The role of scientific testing is to provide information, while professional evaluators are the final authority on all matters that require expert judgment. Decisions about truthfulness and deception are most effective when based on knowledge gained from empirical observation measurement and scientific decision methods. Valid and reliable decisions about truth and deception occur when all available information is utilized and evaluated in an objective, scientific and impartial manner, using the most current information, technology and techniques that are supported by scientific study.


The purpose of a psychophysiological detection of deception (PDD, polygraph) examination is to determine whether the examinee is being truthful or deceptive regarding an issue under investigation. PDD examinations may be conducted as screening exams, and may also be conducted as investigative or evidentiary examinations. This guide establishes recommended procedural elements for conducting a proper psychophysiological detection of deception (PDD) examination.

Referenced Documents

ASTM Standards

  • E1954 Practice for Conduct of Research in Psychophysiological Detection of Deception
  • E2000 Guide for Minimum Basic Polygraph Training and Education
  • E2063 Calibration and Functionality Checks Used in Forensic Psychophysiological
  • Detection of Deception (Polygraph) Examinations
  • E2439 Instrumentation, Sensors and Operating Software Used in Forensic Psychophysiological Detection of Deception (Polygraph) Examinations
  • E2229 Interpretation of Psychophysiological Detection of Deception (Polygraph) Data
  • E2062 PDD Examination Standards of Practice
  • E2031 Quality Control of Psychophysiological Detection of Deception (Polygraph) Examinations

Basic Uses of PDD examinations

The polygraph examination should be a supplement to, not a substitute for, a field investigation.

The effectiveness of the polygraph examination, to a large extent, will be based upon the thoroughness of the investigation, prior to having the person take the examination.

To maximize the effectiveness of the polygraph examination, the investigator and the polygraph examiner should work together as a team.

Polygraph Examiner Qualifications

Members conducting PDD examinations should meet the minimum initial training and continuing educational requirements, including attendance at one professional polygraph seminar on a yearly basis in order to maintain and improve their professional competency as defined in the AAPP Constitution.

To the extent possible, member examiners should be bound individually and collectively to the standards, objectives, and principles of practice of the American Association of Police Polygraphists, Inc., and existing law(s) in their respective jurisdictions. Members should avail themselves, as necessary and allowable, to periodic quality control review through the Association's Quality Control Committee or other quality control procedure.


Prior to any examination, member examiners should consult with investigators, review the circumstances, case facts and relevant documents in order to identify the PDD target issues.

Member examiners should ensure the instrument they intend to use is functioning in accordance with the manufacturer's specifications prior to beginning an examination.

Testing Location and Conditions

Member examiners should strive to conduct all PDD examinations in settings that are sufficiently free from distractions that could interfere with the examinee's attention to the test stimuli.

Pretest Practices

The examiner should:

  • Verify the correct identity of the examinee to the degree practicable.
  • Obtain the written voluntary consent of the examinee prior to testing, and comply with any statutory rights advisement as may be applicable.
  • Assess the mental and physical fitness for testing, to the extent legally practicable and allowable, for each examinee.
  • Terminate any polygraph examination if it becomes apparent to the examiner that the examinee is not suitable for testing.
  • Be familiar and in compliance with governing local, state, and federal regulations and laws and any departmental policy or procedure.
  • Maintain and display an objective approach throughout the PDD exam.
  • Allow the examinee sufficient time to fully explain his/her position as related to the target issues to be tested.
  • Formulate all test questions in compliance with empirically supported field practices and recognized professional practice standards.
  • Ensure the examinee and the examiner have the same understanding of every test question.
  • Spend adequate time to orient the examinee to the PDD instrumentation, examination process, and the expectation or requirement for cooperation during testing.

Minimum Requirements for Polygraph Instrumentation and Software

A minimum of two channels of respiratory activity shall be simultaneously recorded: one thoracic and one abdominal. A minimum of one channel of electrodermal activity, via resistance or conductance, shall be recorded. A minimum of one channel of relative blood pressure (cardiovascular) activity shall be recorded. Additional channels may be recorded but should not replace collection and recording of respiration, electrodermal and cardiovascular activity. Only data channels supported by published research shall be used for the formulation of an opinion.

The instrumentation and software shall permanently record the following: identity of examinee (as applicable), date and time of the examination, start/stop times of recording, pressure settings (when applicable), gain settings (when adjustable), any in-test instructions given examinee, stimulus onset, stimulus identification, end of stimulus, any answer given by examinee, standardized chart markings, and any changes made to the instrumentation or software during recording (such as pressure changes, centering adjustments and gain adjustments).

Test Practices

The polygraph examination should be recorded by audio or audio/visual means in its entirety, from the onset of the pretest interview through the completion of the posttest review, unless prohibited by law, rule or regulation. The recording should be continuous, and any stops or pauses should be explained on the recording. All PDD examination records and recordings shall be retained and maintained for a minimum of one year or longer as may be required by law. Questions should be presented in such a manner as to not influence the examinee's responses.

Member examiners should make and maintain a continuous recording of the data produced during the in-test phase.

Question intervals for deception tests shall allow for a reasonable recovery and stimulus onset to stimulus onset should not be less than 20 seconds, though a minimum of 25 seconds is recommended.

Evaluation Practices

The member examiner should evaluate the test data using a numerical evaluation method for which there are known error and accuracy rates reported in published and replicated research.

Examiners should maintain all records of test data analysis in accordance with ASTM standards or their agency policy.

Examiners should collect a sufficient amount of physiological data suitable for evaluation in compliance with the format utilized.

Post-Test Practices

All suitable physiological data shall be evaluated and considered when formulating an opinion.

A Quality Control (QC) review should follow every polygraph examination to help ensure ethical, professional, and technical polygraph standards are maintained. The review may be conducted within the originating agency, or provided by an outside agency or person, but should be conducted by an examiner who has received training in the format being reviewed. Such reviews should be accomplished without undue influence from the original examiner or other sources.

The QC review should include at least the following:

I. Review of Chart Collection:

  • Global Review of each chart and a blind scored Test Data Analysis
  • Review of the Test Question Construction
  • Confirmation of the correct use of the test’s format
  • Examination of the chart tracings for correct sensitivity, amplitude, cuff pressure, use of activity sensor(s) and inter-question spacing time
  • Review of, or missing chart markings, notations, and notes

 II. Review of Exam Documents:

  • Consent form contains correct date and time, and is signed by examinee and examiner
  • Rights (if used), date, time, and signatures as above
  • Medical info (if any) that was discussed to assess fitness for testing
  • Each Polygraph file should indicate that a QC review of the examination was completed and the result of that review (Concur or Non-Concur).

A more detailed QC review may be necessary as circumstances dictate.

Following collection of all physiological data, a discussion of the examination shall be conducted, as appropriate.