Discrimination performance of statistical values used in the concealed information test studies

Abstract

The concealed information test (CIT) estimates whether an examinee knows crime-relevant information on the basis of diŠerences in physiological responses between the crime-relevant and irrelevant information. To examine the diŠerences in physiological responses, this study used the following four statistical values: Lyk-ken's scores, likelihood ratios, eŠect sizes, and p values of randomization tests. A total of 152 participants, 80 of whom actually knew information related to a mock theft, received a CIT about the theft. From these CIT data, the four statistical values were calculated. On the basis of these values, whether each participant knew the theft-related information was ascertained. High correct discrimination ratios were seen for eŠect sizes (92.4) and p values of randomization tests (90.6) compared to Lykken's scores (83.2) and likelihood ratios (74.8). Areas under the receiver operating characteristic curves were also greater for eŠect sizes (0.919) and p values of randomization tests (0.928) than for the other statistical values. These results suggest that eŠect sizes and p values of randomization tests are promising for examining the physiological diŠerences in the CIT.