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Although polygraph examinations continue to be used widely

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concerns are growing about the errors made by examiners.

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To study this issue, researchers obtained the actual polygraph records

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of 50 criminal suspects who were later found to be innocent

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and 50 suspects who later confessed to their crimes (all suspects had been accused of theft).

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The researchers asked six expert polygraph examiners to decide

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which suspects appeared to be guilty on the basis of the polygraph record.

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How well did the polygraph experts do at detecting lies?

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Overall, the polygraph experts correctly categorized about two-thirds of the suspects

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(76% of the guilty individuals and 63% of the innocent), as shown by the solid bars on the graph.

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The experts made two types of errors:

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Misses, in which they failed to identify 24% of the guilty suspects

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and False Alarms, in which they incorrectly accused 37% of the innocent people of lying.