Questions:
1. In the “simulation study with Mixed structure”, two different specifications were applied to the items (page 395, paragraph 2). How to specify the dimension and structure for items? What about if some items were correctly specified and some were incorrectly specified?
2. In the “Discussion”, it said that the assumption of simple structure is strong and can be expected to be violated in many cases. How to verify the structure of the test?
3. Taking all simulation results together, the most serious problem was the over-estimation of correlation coefficients between dimensions when mistakenly specified a MST as SST (table 8). Whether it is able to say that, if the correlation between dimensions is not an important concern in research, then it is no matter which approach to be used?