This is a discussion on the paper titled “Assessing feed-in tariffs on wind power installation and industry development in Taiwan” published by Hsu et al. In the discussed paper, there were several missing variables in the historical test of the system dynamics (SD) model, and thus the test was not integrated and valid. Additionally, the simulated results of the missing variables were used as important indexes to observe the behavior of the SD model. Therefore, it was highly likely that the solution and related policy analysis based on the simulated results were incorrect. Accordingly, the present study illustrated the structure characteristics of the SD model with respect to the fore-mentioned problems, discussed the reason for missing variables and proposed a method to assess whether or not the historical test was integrated. Finally, after a careful analysis, this study offered suggestions to perfect the historical test proposed in the discussed paper.