How Does Internet Use Improve Mental Health among Middle-Aged and Elderly People in Rural Areas in China? A Quasi-Natural Experiment Based on the China Health and Retirement Longitudinal Study (CHARLS)
Round 1
Reviewer 1 Report
The authors aimed to examine the effect of Internet use on the mental health of middle-aged and elderly people in rural China based on the difference-in-differences method. They found Internet use effectively improves the mental health status of middle-aged and elderly people; Internet use has a more obvious effect on the mental health of the elderly; Playing games, watching videos and reading news have different effects on the mental health of middle-aged and elderly people in rural China. This is a well-written paper.
I have several comments and questions:
1. Line 144, “By observing the changes of Internet users (treat group) and non-Internet users (control group) before and after using the Internet, we concluded that the mental health changes of the Internet users (treat group) were affected by the Internet, while the mental health changes of the non-Internet users (control group) were not”. Please explain why non-Internet users (control group) use the internet without effects on mental health changes.
2. Line 204, the mental health level, age, the prevalence of chronic diseases, and education and consumption level of the treated group are all better than the control group, please explain how to separate these effects from the effects of internet use in the treatment group.
Author Response
Please see the attachment.
Author Response File: 
Author Response.docx
Reviewer 2 Report
Dear Authors,
This is a very interesting paper and of particular interest with the Chinese population ageing. The design of the study appears robust, and you demonstrate a sound methodological approach.
There are times though when you assume the reader knows the Chinese context and more explanation is required to assist the international reader, for example:
p. 1, line 38: “during the economic and social transition period…….” – what is this period?
p. 2, line 58: what are the intergenerational programs?
Line 60-61 what do you understand to be "child support".
The tables also need more explanation/description -- the quantitative language needed more discussion.
Unsure what referencing protocol was used - the year of publication was not cited with the author and the reference list was neither alphabetical nor numerically presented.
I think attention to these elements would enhance the fluency of the paper - well done on your work.
Author Response
Please see the attachment.
Author Response File: Author Response.docx
Reviewer 3 Report
Suggestion for table 2: it is a little bit odd to calsculate means of nominal variables. My suggestion is to use histograms for nominals.
Author Response
Please see the attachment.
Author Response File: Author Response.docx
