The manuscript states “The results demonstrated that the overall Cronbach’s α coefficient for all scale items was 0.842(> 0.8), showing good reliability.” However, the study used a 5-point Likert scale for a post-class perception questionnaire administered only to the SCD group. Cronbach’s α is appropriate for assessing internal consistency, but this does not validate the primary outcome measure (test scores). Furthermore, the paper provides no evidence that the pre/post-test scores were validated for reliability (e.g., test-retest) or that the tests were equivalent in difficulty across academic years. Given that the pre/post-tests were different (post-test had “increased difficulty”), comparing score gains is invalid. How can you justify comparing score gains when the tests were not equivalent?
