A Trial of Voluntary Polygraphy Testing in 10 English Probation Areas

Abstract

Sex offenders taking part in treatment programs in 10 probations areas of England were asked to undertake polygraph testing on a voluntary basis. Over a 2-year period 347 offenders attended for testing (43% of those eligible). Outcome was compared with offenders from four probation areas where polygraphy was not introduced. Case managers of polygraphed offenders reported new disclosures relevant to supervision being made in 70% of first tests, compared with 14% of case managers of nonpolygraphed offenders who reported new disclosures in the preceding months (odds ratio [OR] = 14.4, confidence interval [CI] = 8.5, 24.5). Of the disclosures made during polygraph testing, 27% were rated as being of “medium” severity and 10% “high.” Polygraph and nonpolygraph case managers reported making revisions in risk assessment with similar frequency, but nonpolygraph case managers were much more likely to consider risk to have reduced while changes in risk assessment made by polygraph case managers were usually upwards (OR = 5.0, CI = 1.7, 14.6). Case managers of polygraph offenders reported more treatment changes than case managers of the comparison group (OR = 3.1, CI = 1.6, 6.0), which were attributable to the polygraph test. Case managers rated polygraphy as “somewhat” or “very” helpful after 93% of tests for which we had information.