Equivalence of the German and the French Versions of the Self-Report Symptom Inventory

Against the background of the growing importance of symptom validity assessment both in forensic and clinical or rehabilitation contexts, a new instrument for identifying overreporting was developed. In order to study the equivalence of the German and the French versions, we divided the item pool of the Self-Report Symptom Inventory (SRSI) into two presumably equivalent half-forms. A sample of 40 adult bilingual Swiss nationals with a mean age of 39.9 years responded honestly to one of the half-forms in German and to the other in French. In a subsequent experimental malingering condition, they were asked to simulate sequelae of a whiplash injury and to respond to the SRSI again. In both conditions, they also filled out the Structured Inventory of Malingered Symptomatology (SIMS). The results showed no differences between the two language versions in both conditions. Classification accuracy was very high (100% specificity, 90% sensitivity for the standard cutoff score). Reliability estimates were 0.93 for endorsement of genuine symptoms and 0.97 for pseudosymptom endorsement. In the malingering condition, the correlation between the number of reported pseudosymptoms and the SIMS scores was 0.69. The current results add to the database available for the SRSI and support the appropriateness of the French version.