The polygraph, its use in cases of alleged sexual abuse: an exploratory study

The study's objective was to examine the relationship of polygraph findings to other indices of likelihood of sexual abuse and to case decisions by prosecutors, child protection workers, and professional evaluators.

This is an exploratory study of 42 cases with sexual abuse allegations and polygraph results. Case record data were abstracted and coded, including polygraph results, child interviews, medical examinations, protective services records, police investigations, and professional evaluations. Descriptive statistics, bivariate analyses, and multivariate analyses were employed.

Polygraph findings were unrelated to other evidence of likelihood of sexual abuse, that is to the child's statements or demonstrations of sexual abuse, medical evidence, psychological symptoms, or indicators of sexual abuse from sources other than the child. When alleged offenders passed polygraphs, criminal prosecution was not sought. However, failing polygraphs was not predictive of criminal prosecution. Decisions by child protective services to substantiate or not were weakly related to polygraph findings and consistently related to any indicators of possible sexual abuse. Decisions by professional evaluators about sexual abuse were best predicted by children's psychological symptoms.

The findings reinforce already expressed reservations about the polygraph's utility in sexual abuse decision-making. Additional research is needed on decisions about the likelihood of sexual abuse.