Table 1 Steps of selecting methods

Method 1

Step1: The 8 indexes were selected as independent variables, and the top 3 items were selected

Step2: The items with the highest frequency in the top 3 of each index are selected to form the simply questionnaire

Step3: The core group discussed the questionnaire and reserved items, and submitted the discuss results to the expert group up for review and determine the final reserved items

Method 2

Step1: Except for expert survey, items that are suggested to be deleted by any of the 7 indexes will not be retained

Step2: For the items retained in the step 1, the top 3 items were selected according to the assignment value of the expert survey to form the simply questionnaire

Step3: Same as step 3 of selecting method 1

Method 3

Step1: According to the 3 methods including expert survey, CTT and IRT, the top 3 items will be screened respectively

Step2: The items that were selected in the top 3 most times by 3 methods will be selected to form the simply questionnaire

Step3: Same as step 3 of selecting method 1

Method 4^a

Step1: Except for expert survey, items that are suggested to be deleted by any of the 2 method will not be retained

Step2: For the items retained in the step 1, the top 3 items were selected according to the assignment value of the expert survey to form the simply questionnaire

Step3: Same as step 3 of selecting method 1