Research On The Characteristics Of Traditional Chinese Medicine Body Scale Based On Project Response Theory

Objective:As an important theory in the field of psychological measurement, item response theory (IRT) estimated the abilities or latent traits of subjects through the calculation of mathematical model according to the actual answer reaction results. Currently, although IRT is widely used in the development, evaluation, modification and test of scale about health, the IRT study about Constitution of Chinese Medicine Questionnaire (CCMQ) is rare, and the published evaluation studies about CCMQ were generally focused on the approaches of classical test theory (CTT). This study, through the method of IRT, explore the characteristics of CCMQ items such as discrimination, difficulty and differential item functioning (DIF), in order to supply the comprehensive evaluation CCMQ, perfect the identification theory of constitution of traditional Chinese medicine (TCM), and provide the reference for further study to CCMQ.Methods:The study included 1114 patients who received physical examination in center for treatment of diseases in Zhuhai hospital of Guangdong province TCM hosipital and center for health management of the first affiliated hospital of Anhui University of TCM as examinees, then tested the basic information and CCMQ in one questionnaire. Statistical analysis included the examinees’ basic descriptive statistics, parameters estimation based on IRT and differential item functioning (DIF) analysis of different gender, age (young or middle and old).Results:The basic statistics shows that examinees were prefer to focus on the first three options, and the low probability was showed on option 5. The parameter analysis in IRT showed (1) on discrimination aspects, ①in all examinees, except item 1 and the item 53 outside, parameter a are all above 0.60 ②in male examinees, except item 1, item 53 and the item 58 outside, parameter a are all above 0.60 ③in female examinees, except item 1, item 35 and the item 53 outside, parameter a are all above 0.60 ④in young examinees, except item 1 and the item 53 outside, parameter a are not below 0.60 ⑤in middle and old examinees, except item 1, item 28, item 45 and the item 53 outside, parameter a are all above 0.60, above items which discrimination parameters are low, its item character curves (ICC) are flat, loose or clutter; (2) difficulty aspects, ①in all examinees, item 1 and the item 53 of difficulty parameter b1 are below -3.00, item 1, item 13, item 21, etc. a total of 8 items’difficulty parameters b4 are above 4.00 ②in male examinees, item 1 and the item 53 of difficulty parameter b1 are below -3.00, item 1, item 4, item 13,etc. a total of 12 items’difficulty parameters b4 are above 4.00 ③in female examinees, item 1, item 8 and the item 53 of difficulty parameter b1 are below -3.00, item 1, item 13, item 21, etc. a total of 12 items’difficulty parameters b4 are above 4.00 ④in young examinees, item 1 and the item 53 of difficulty parameter b1 are below -3.00, item 1, item 32, item 35, etc. a total of 6 items’difficulty parameters b4 are above 4.00 ⑤in middle and old examinees, item 1 and the item 53 of b1 are below -3.00, item 1, item 4, item 12, etc. a total of 20 items’ difficulty parameter b4 are above 4.00, above items which difficulty parameters b4 are high, its item character curves perform the right partial. As DIF analyses showed, item 1, item 2, item 6, etc. a total of 12 items are exists DIF in different gender and the different age subject groups, except these 12 items outside, item 5, item 17, item 18, etc. a total of 12 items in different gender groups exist DIF, item 8, and item 9, item 11, etc. a total of 8 items in different age groups exist DIF.Conclusion:The characteristics of CCMQ items are not same at all. Almost all of the items in CCMQ perform high discrimination skills; most of the items have moderately difficulties, although some items’ difficulties are higher than normal standard or exist DIF, the overall performance of CCMQ is pretty well. The items with low discrimination, high difficulties, or DIF, may related to factors such as the level of health, the character of subject groups, which need further discussion to prove. Such items need to be fully paid attention to in the future development and revision work about CCMQ.