of the Polygraph
accuracy takes two conditions into account – Validity and Reliability.
refers to whether a test does indeed measure what it claims to.
refers to the extent to which a test (or instrument) is consistent in
its measures. It also addresses the issue of consistent results if
another examiner retests a person.
evidence supports the high validity of polygraph examinations. However,
a valid examination requires a combination of a properly trained
examiner, state of the art polygraph instrumentation, and the proper
administration of an accepted testing and scoring system.
Ansley reported that from all studies of real cases conducted from 1980
to 1990, which involved 10 studies considering 2 042 police and private
examinations using a variety of techniques administered in the US,
Canada, Israel, Japan and Poland, validity was 98%.
of police and private examinations, where independent evaluators
rescored polygraph charts concluded that reliability was 95%.
Ansley showed average validity for 1 964 people in criminal cases
was 96.3% and the average validity for 1 113 people in laboratory
cases was 93.6%.
Polygraph Association has a compendium of research studies available on
the validity and reliability of polygraph testing. The 80 research
projects listed, published since 1980, involved 6 380 polygraph
examinations or sets of charts from examinations. Researchers conducted
12 studies of the validity of field examinations, following 2 174
field examinations, providing an average accuracy of 98%.
conducted 11 studies involving the reliability of independent
analyses of 1,609 sets of charts from field examinations confirmed by
independent evidence, providing an average accuracy of 92%.
conducted 41 studies involving the accuracy of 1,787 laboratory
simulations of polygraph examinations, producing an average accuracy of
80%. Researchers conducted 16 studies involving the reliability of
independent analyses of 810 sets of charts from laboratory simulations
producing an average accuracy of 81%. Tables list the authors and years
of the research projects, which are identified fully in the References
Cited. Surveys and novel methods of testing are also mentioned.
is important to note that the term Polygraph does not apply to Voice
Stress Analyzers or CVSA’s. Please refer to the section of this site
named “Frequently Asked
Questions” for more information on CVSA’s and our stance on