Objective To analyze the general module of quality of life instruments for chronic diseases(QLICD-GM) using item response theory(IRT).Methods A total of 1 024 patients each with one of the eight chronic diseases were measured by QLICD-GM.Samejima′s Graded Response Model and software MULTILOG were used to calculate difficulty coefficient,discrimination coefficient,and information power,and to draw item characteristic curve.Results Of all 30 items,the discrimination coefficient fell between 1.17 and 1.88,and ...