The European project PSIP (Patient Safety through Intelligent Procedures in Medication) aims at semi-automatically identifying and preventing ADE. Automatically detected Adverse Drug Events have to be reviewed and validated by human experts. Existing methods usually have the experts review the cases and document their rating in a structured form. One of the limitations of these methods is their poor ability to analyze and clear the disagreements between the experts and the system. This paper presents an innovative Human Factors based method to support the review by clinicians and pharmacologists of these automatically detected ADE. We use think aloud methods and portable labs to track and record the experts reasoning and their reviewing cognitive procedures. We present preliminary results obtained with this method, which allows identifying the key data and information used to characterize the ADE. This method provides useful feedbacks allowing a continuous refinement and improvement of the automated detection system.