Skip to content
Joan Advincula

Joan Advincula

Technology. Criminology. Education.

  • Home
  • Crim Notes
    • ChFo 102 Character Formation 2
      • Leadership and Management
        • Leadership vs Management
        • Principles of Leadership
        • Theories of Leadership
        • Leadership Styles
        • Management Styles
        • Efficient Management
        • Qualities of Leaders and Managers
      • Administration
        • Principles of Administration
        • Theories of Administration
        • Functions of Administration
        • Police Management
        • Division of Work
        • Authority and Responsibility
        • Unity of Command
        • Scalar Chain
      • Decision-Making
        • Characteristics of Decision-Making
        • Principles of Decision-Making
        • Guidelines of Decision-Making
        • Individual vs Group Decision-Making
        • Police Decision-Making
    • CrDI 103 Specialized Crime Investigation 2
      • Crimes Against Property
      • Review on Evidence
    • FrSc 105 Lie Detection Techniques
      • Introduction to Lie Detection
        • Psychology of Lying
        • Lies and Liars
        • Ancient Methods of Detecting Deception
        • Other Methods
      • Fundamentals of Polygraphy
        • Definition of Relevant Terms
        • The Nervous System
        • Theory Behind the Polygraph
        • The Polygraph Instrument
        • General Uses
      • Reliability and Validity
        • Scientific Validity
        • Legal Aspects of Polygraph Use
        • Pros and Cons
      • Question Formulation for Polygraph Examination
      • Conduct of Polygraph Examination
    • FrSc 106 Forensic Ballistics
      • Overview of Forensic Ballistics
        • History of Forensic Ballistics
        • Relevant Personalities
        • Branches of Ballistics
      • Firearms
        • Characteristics of Firearms
        • Classifications of Firearms
        • Firearm Markings
  • Home
  • Crim Notes
  • FrSc 105 Lie Detection Techniques
  • Reliability and Validity
  • Pros and Cons

Pros and Cons

Advantages

  • The polygraph instrument is a legacy system with a long history of use in law enforcement.
  • While it may be challenged at court, polygraph testimony can be allowed.
  • There has been a decrease in the cost of these machines due to market competition.
  • It is a well-known scientific investigation tool due to its high exposure in the media and popular culture.

Disadvantages

  • Due to its increased popularity, its reputation has been tarnished especially due to some shows that use the polygraph instrument ineptly.
  • It is subject to countermeasures, false positives, false negatives, and inconclusive results. As already mentioned in a previous lesson, research has shown that its validity is immeasurable.
  • The accuracy rates of the test can vary widely ranging from 50% to 87.5%.
  • The examination can be very lengthy and requires the subject to remain still while hooked up to numerous sensors thereby potentially altering readings as the exam goes longer.
  • Training to become a polygraph examiner can be a costly and lengthy process, yet there is no recertification program to determine continuing compliance of those already certified.

Limitations

As mentioned in previous lessons, the polygraph instrument is not an absolute tool. Instead, it is but an investigative tool. A good investigator would do well to remember the following limitations of this machine:

  1. It is an investigative aid, never a substitute for an investigation.
  2. It is not a lie detector, but a scientific diagnostic instrument.
  3. It does not determine facts, only diagnostic reactions.
  4. It only records responses, not determines the truth.

The test must not be given until enough facts of the case have been established to permit an examiner to prepare a complete set of suitable questions. The test should not be given without voluntary consent of the subject nor should it be given before the accusations could be explained to the subject. No indication to any person or place in any report that a person will be considered guilty because he refused to take the test.

Additionally, the test should not be conducted on any unfit subject nor should it be used for the mental or physical evaluation of any person.

Ethical Issues

As already mentioned multiple times, the polygraph instrument is not a lie detector machine. Rather, it is simply a machine that senses and records the physiological changes in the subject. As such, the test and its interpretation are subjective in nature. Due to this, erroneous results can potentially lead to the incarceration of innocents if it is considered the sole reasoning behind a conviction.

Leave a Reply Cancel reply

Your email address will not be published. Required fields are marked *

Copyright © 2023 Joan Advincula.

Theme: Oceanly by ScriptsTown