The External Validity of Studies Examining the Detection of Concealed Knowledge Using the Concealed Information Test

The criterion validity of the Concealed Information Test (CIT) and its ability to differentiate between individuals possessing knowledge of critical items and those unaware of these items has been demonstrated in many laboratory experiments. However, despite impressive validity estimates resulting from these studies, the external validity of CIT laboratory experiments has been repeatedly questioned. This chapter reviews various attempts to examine the external validity of CIT research, either through studies conducted under realistic settings or by controlled experiments manipulating factors that distinguish between the typical laboratory environment and the realistic forensic application of the CIT. In most cases, the results of these studies support the external validity of the CIT as a valid tool.