Swiss population-based reference data for six symptom validity tests

Symptom validity test (SVT) results should be resistant against sociodemographic variables. Healthy, cooperative respondents should be able to pass these tests. The purpose of the study was to collect reference data for a selection of SVTs (Medical Symptom Validity Test, Structured Inventory of Malingered Symptomatology, Amsterdam Short-Term Memory Test, Emotional Numbing Test, Reliable Digit Span, Maximum Span Forward). A representative population-based sample of 100 German speaking Swiss citizens from 18 to 60 years of age was investigated. Multiple regression analyses revealed that age and verbal intelligence had an effect on various SVTs, whereas sex and education did not. The rate of positive test scores ranged from 1% (Emotional Numbing Test, Structured Inventory of Malingered Symptomatology) to 4% (Maximum Span Forward). One of the pertinent questions is if such positive results in reference or normative samples represent false positives or true positives and how to deal with the problem.