• Concealed Information Test (CIT);
  • Guilty Knowledge Test (GKT);
  • skin conductance response (SCR);
  • heart rate deceleration;
  • respiration line length (RLL);
  • event-related potential (ERP);
  • P300;
  • meta-analysis


The Concealed Information Test (CIT) uses psychophysiological measures to determine the presence or absence of crime-related information in a suspect's memory. We conducted a meta-analysis on the validity of the CIT based on four physiological measures—skin conductance response (SCR), respiration line length (RLL), changes in heart rate (HR), and enhanced amplitudes of the P300 component of the event-related potential (P300). This meta-analysis relied on laboratory studies that used either the mock-crime or the personal-item paradigm. Results showed a mean effect size (d*) of 1.55 for SCR, 1.11 for RLL, 0.89 for HR, and 1.89 for P300. However, P300 outperformed SCR only in the personal-item paradigm, but not in the mock-crime paradigm. Motivation level, number of questions, publication year, and the inclusion of innocent participants emerged as significant moderators for the SCR, while only the type of paradigm used moderated the P300 effect.