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The authors have addressed all of the reviewers' comments and made reasonable amendments throughout the review process.
[# PeerJ Staff Note - this decision was reviewed and approved by Jafri Abdullah, a PeerJ Section Editor covering this Section #]
As recommended by one of the reviewers, please add dollar value of parents’ monthly income (in MYR) in the footnote of the table for international reach and understanding.
The authors have addressed all comments
Thank you for providing the reference (Zhang, 2016) that supports statistical analysis procedures. While literature does support this approach, please bear in mind that it is still debated and may not be universally accepted. To strengthen your writing justify your inclusion of variables based on theory/clinical knowledge.
Thank you for providing support for the use of non-standardised methods to capture data. Please consider using standardised measures for future studies.
These have been sufficiently addressed in the limitations section
none
no comment
the criteria on how the students academic performance was reported was not standardised.
no comment
no comment
The primary concern relates to statistical analysis and raising the p-value threshold to 0.25, this should be reduced down to the conventional 0.05 and discussion should reflect these changes.
**PeerJ Staff Note:** Please ensure that all review, editorial, and staff comments are addressed in a response letter and that any edits or clarifications mentioned in the letter are also inserted into the revised manuscript where appropriate.
The theme of this article has already been explored in previous papers. However, before acceptance, I consider that some adjustments are important in this manuscript.
In the sampling process, the authors need to mention the test power in this procedure. The study used convenience sampling, which may not adequately represent the entire population of dental students in Malaysia. This method might introduce selection bias, as those who voluntarily participate might differ systematically from those who do not.
For the economic income variable, I suggest the authors convert it to US dollars (it concerns a global comprehension score).
And how was sleep efficiency among the students in this research sample? Was this efficiency different concerning the analyzed variables?
The criteria (P-value < 0.25) used for variable inclusion might result in overlooking important factors related to sleep quality. Employing stricter criteria or incorporating prior theoretical understanding could strengthen the model's reliability and validity.
Reporting is clear and in general, literature references are fair. However, in some cases, more recent literature could be included - notably the first paragraph of the introduction. In discussion, some areas are unclear and require further clarification (please see section 3.).
Suggestions for introduction
Line 27-29 Author encouraged to use a more current definition of sleep quality. [is sleep quality correctly defined?]. More writing is needed to definition sleep quality and discuss the recent literature examining its role in health, as opposed to generalised sleep discussed in line 32.
Line 37, 38 some concerns for typos and use of italics for in-text citations (e.g. Shen,Tam & Hon, 2010 which should be Shen, Tam & Hon, 2010). Please ensure consistency in referencing format.
[rationale should discuss the relationship between sleep duration and sleep quality, particularly as students/young adults have shorter sleep duration than middle aged adults. Further, there is variation in populations group in particular regions (Japan, east Asia for instance have shorter sleep duration than Western/US) Cheung, B. Y., Takemura, K., Ou, C., Gale, A., & Heine, S. J. (2021). Considering cross-cultural differences in sleep duration between Japanese and Canadian university students. PloS one, 16(4), e0250671. https://doi.org/10.1371/journal.pone.0250671
Rationale should discuss whether differences in sleep quality apply to dental students specifically – i.e. do dental students report shorter sleep/poorer sleep quality than other students?
Line 60. It is helpful to summarise the evidence you have presented in lines 48-59 before moving forward. that supports your rationale for investigating medical students before moving to identify the literature gap.
Line 73 please provide full terms before abbreviations i.e. CGPA
Original research and research question is defined fairly well. The writing could convey a stronger rationale for the study. Ethical concerns addressed. However, the investigation was not performed to a high technical standard. The primary concern relates to statistical analysis and raising the p-value threshold to 0.25. This practice is non-standard. The conventional significance level, commonly set at 0.05, represents the probability of obtaining results as extreme as the observed results, assuming that the null hypothesis is true. A higher p-value threshold, such as 0.25, increases the likelihood of accepting null hypotheses and may lead to a higher rate of false positives.
Further the use of non-standardized methods to capture data i.e. physical activity, alcohol, caffeine raises concerns for the reliability and validity of the data. This excludes assessment of sleep using PSQI.
Suggested improvements for methods are outlined below:
Line 88 Ensure a complete description of inclusion and exclusion criteria for participant recruitment.
Line 107 -126. For all variables, the authors should describe the level of measurement, i.e. age (years), smoking, caffeine intake, exercise etc. This is particularly important with reference to M40 socioeconomic group as this variable is not defined correctly. For parents income (stated in participant facing questionnaire), was this defined as annual income?
Line 110 Rationale for BMI cutoff values for overweight should be included (see WHO Expert Consultation (2004). Appropriate body-mass index for Asian populations and its implications for policy and intervention strategies. Lancet (London, England), 363(9403), 157–163. https://doi.org/10.1016/S0140-6736(03)15268-3.
Line 121 for published questionnaires, the authors whether or not reliability analysis was performed, i.e. Cronbach alpha values
Line 139 Please also describe your final sample and how many participants were excluded after checking/cleaning
Line 153 please justify your decision to set a larger P-value (i.e from research literature). There is concern for raising the p-value for risk of type 1 error, spurious associations, overfitting, and interpretability (see Durand, C. P. (2013). Does raising type 1 error rate improve power to detect interactions in linear regression models? A simulation study. PloS one, 8(8), e71079). Consider alternative approaches see Halsey, L. G. (2019). The reign of the p-value is over: what alternative analyses could we employ to fill the power vacuum? Biology letters, 15(5), 20190174.
Line 155-159 please describe whether or not your model met the assumptions described. Here a reference to supplementary data can be included.
Please see concerns discussed in section 2.
Due to the statistical analysis methods used, caution should be applied when interpreting the data. The results, particularly the multiple logistic regression model, should be fully described. Suggestions outlined below
Line 167 – data for weekly exercise frequency should be included in Table 1
Line 169 ‘drink’ should be ‘drank’
Line 189 and table 6, the 5 variables included in the multiple logistic regression should be described.
Line 209 is perhaps not relevant to study sample
Line 213-228 should identify cultural differences in sleep practices that may impact sleep outcomes. This is briefly discussed in 231-238 but should be expanded and interpreted.
Line 283 – 304, concern for interpretation of the study findings given concerns highlighted in methods. Re-analysis of the results may yield different findings.
Limitations should acknowledge constraints of measurement levels assessed in the questionnaire. The units of measurement for variables like exercise, alcohol etc. are difficult to interpret against other studies. For instance, physical activity is typically reported as minutes of moderate-to-vigorous or moderate exercise per week Meh, K., Jurak, G., Sorić, M., Rocha, P., & Sember, V. (2021). Validity and Reliability of IPAQ-SF and GPAQ for Assessing Sedentary Behaviour in Adults in the European Union: A Systematic Review and Meta-Analysis. International journal of environmental research and public health, 18(9), 4602. https://doi.org/10.3390/ijerph18094602
Table 1
Consider reporting age as mean ± SD and range (minimum to maximum)
Footnote should describe all abbreviations (i.e. B40, M40, T20)
The rationale of the study is fair and contributes to an understanding of the factors associated with sleep in student populations. However, to ensure accuracy, transparency and reproducibility, the authors are encouraged to use standardized questionnaires and apply a conventional approach of using p<0.05, specifically to reduce risk of spurious associations.
The majority of the article exhibits a strong command of English structure; however, a few sentences, particularly those preceding the aim and a few others, require revision for improved grammar and structure.
Was there a guideline provided to students for establishing their academic performance levels? In other words, when students selected "good," what was the GPA or grade range associated with that designation?
No comment
To enhance result clarity, I recommend incorporating graphs and figures alongside tables for a more visually comprehensive presentation.
At in this sentence
213 The current study showed that 51.6% of students reported having poor sleep quality, which was 214 lower than studies done among medical students in Pakistan and dental students in Saudi Arabia 215 and Brazil where 64.2%, 72.5%, and 65.2%, of the students have poor sleep quality(Elagra et al., 216 2016; Maheshwari & Shaukat, 2019; Muñoz et al., 2023).
The references order need revision
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