Polygraph Validity Research
The American Polygraph Association (APA) believes that scientific evidence supports the validity of polygraph examinations that are conducted and interpreted in compliance with documented and validated procedure. Thus, such examinations have great probative value and utility for a range of uses, including criminal investigations, offender management, and selection of applicants for positions requiring public trust. The APA Standards of Practice set some of the highest professional requirements for its members to ensure their polygraph services are valuable, reliable, and promote ethically responsible practices. The APA also produces a variety of model policies that represent the current understanding of best practices, and makes them widely available so that polygraph examiners (both APA members and non-members) and their clients can be aware of what constitutes a valid examination process. The APA believes that well informed departments, agencies, and clients will insist on APA members for their polygraph services.
Recently the APA undertook an exhaustive review of all of the peer-reviewed publications on polygraph testing that represented field practices and which met the requirements of the APA Standards of Practice. A meta-analysis was conducted, and a report was completed in late 2011. An executive summary of the report is freely available to the public through the APA website.
The executive summary reports that 38 studies satisfied the qualitative and quantitative requirements for inclusion in the meta-analysis. These studies involved 32 different samples, and described the results of 45 different experiments and surveys. They included 295 scorers who provided 11,737 scored results of 3,723 examinations, including 6,109 scores of 2,015 confirmed deceptive examinations, 5,628 scores of 1,708 confirmed truthful exams. Some of the cases were scored by multiple scorers and using multiple scoring methods. The data showed that techniques intended for event-specific (single issue) diagnostic testing produced an aggregated decision accuracy of 89% (confidence interval of 83% - 95%), with an estimated inconclusive rate of 11%. Polygraph techniques in which multiple issues were encompassed by the relevant questions produced an aggregated decision accuracy of 85% (confidence interval 77% - 93%) with an inconclusive rate of 13%. The combination of all validated PDD techniques, excluding outlier results, produced a decision accuracy of 87% (confidence interval 80% - 94%) with an inconclusive rate of 13%. These findings were consistent with those of the National Research Council’s (2003) conclusions regarding polygraph accuracy, and provide additional support for the validity of polygraph testing when conducted in accordance with APA Standards of Practice.