The study reports improved IPC knowledge and PPE skills after using D-B_EPCD, but in my opinion, to strengthen the study, you should apply more rigorous analytical methods to support a causal interpretation of these improvements. The current analysis does not sufficiently address potential confounding factors such as parallel training efforts, general institutional learning, or pandemic-related behavioral changes over time. Additionally, the reported average system usage frequency (1.74 times/week) raises questions about the relationship between system engagement and outcomes; was there a measurable dose-response effect? To better substantiate your conclusions, you should consider using approaches such as mixed-effects modeling or interrupted time series analysis to control for temporal trends and confounders, and to model the relationship between system use intensity and skill acquisition.
The previous reader raised valid concerns regarding the lack of rigorous statistical controls and causal inference in your study. While your results suggest significant improvements in IPC knowledge and PPE skills following the use of D-B_EPCD, the analysis as it stands does not convincingly demonstrate that these outcomes can be attributed specifically to the system itself. The absence of a control group, lack of adjustment for confounding variables (e.g., external IPC campaigns, institutional policy shifts, or broader pandemic-induced behavioral changes), and limited modeling of system usage intensity (average 1.74 times/week) weakens the causal claims.
Although your discussion acknowledges limitations such as the absence of a control group and plans for future improvements, this post-hoc justification does not address the immediate concern that without modeling confounders or applying robust temporal analyses (e.g., interrupted time series, mixed-effects regression), it is impossible to determine whether observed improvements stem from the intervention or other contextual factors.
Given the reported system usage frequency (1.74 times/week) and the study’s lack of a control group or temporal modeling, how can you distinguish between the effects of the D-B_EPCD system itself and other possible confounding variables (e.g., concurrent institutional changes, pandemic-related behavioral shifts, or generalized IPC awareness) that may have influenced the observed improvements in IPC knowledge and PPE skills? Moreover, did you explore any dose-response relationships between system usage intensity and learning outcomes, which could strengthen the argument for system-specific effects? If not, how do you justify attributing causality to D-B_EPCD in the absence of such analysis?