The assessment of content validity is not described in theoriginal paper. Authors report adequate feasibility, test-retestreliability and construct validity in a population of patientswith chronic liver disease.61 High correlations were detectedbetween the “Joint pain”, “Sleepiness during the day” and“Depression” symptoms severity and corresponding hindranceitems. However, authors demonstrated larger impact of hindrance items on overall QoL score than the symptom severityitems, which leads to the conclusion that different items of theinstrument measure different aspects of QoL.Internal consistency is reported as high with Cronbach’s a>0.79. Spearman correlations suggested strong convergent relations between symptom severity items and their accompanying symptom hindrance items (0.52–0.80).6