Symptom Checklists "O" and "S"
Symptom Checklists "O" and "S" (KO "O" and KO "S") are self-report questionnaires used for determining the presence of neurotic disorders, assessment of changes of symptom intensity, and evaluation of effectiveness of treatment in terms of symptom reduction or intensification. The KO "O" derives from SCL-90-R. In comparison to SCL-90-R it differs mainly in the lack of items referring to psychotic symptoms and inclusion of questions about the most common symptoms in patients with neurotic disorders observed between 1975 and 1978.
Source: Wikipedia — Symptom Checklists "O" and "S" (CC BY-SA 4.0)