“…Studies have shown that the accuracy of parameter estimation produced by the testlet response theory (TRT) model is higher than the traditional item response theory (IRT) model where LID was present ( Bradlow et al, 1999 ; Wainer and Wang, 2000 ; Wainer et al, 2000 ; Zhang, 2010 ; Koziol, 2016 ). However, numbers of studies were based on dichotomous items ( Wainer and Wang, 2000 ; Rijmen, 2009 ; Cao et al, 2014 ). Researchers have found that although the polytomous IRT models suffer the problem of losing response pattern information, they are still much easier in interpretation and implementation ( Sireci et al, 1991 ; Zenisky et al, 2002 ; Cao et al, 2014 ).…”