2798 – Differential item functioning of the chinese version of the somatosensory amplification scale among adolescents across grade levels

Introduction Tam et al. (2011)[1] recently reported the invariance of the one-factor model of the Chinese version of the Somatosensory Amplification Scale (ChSAS). The objective of this paper is to further examine the item-level equivalence of the ChSAS in a sample of Chinese adolescents across grade levels. Methods The ChSAS was administered to 500 Chinese adolescents. Differential item functioning (DIF) analysis was performed to identify any uniform and non-uniform differences on the 10 ChSAS items among adolescents across different grade levels. Results After a Bonferroni adjustment of p value (=0.0007, i.e., 0.05/70), results of DIF analyses showed that there is no uniform (all F s ranging from 0.17–2.15, p s > 0.09) or non-uniform (all F s ranging from 0.47–1.76, p s > 0.02) difference on the 10 ChSAS items. Conclusions The four different grade level groups used the scale comparably, without showing any difference on item properties. These findings further substantiate the use of ChSAS as a valid and reliable instrument among adolescents across grade levels.