Skip to main content
PMC home page
PLOS ONE logoLink to PLOS ONE
. 2021 Mar 10;16(3):e0247104. doi: 10.1371/journal.pone.0247104

Should I study or should I go (to sleep)? The influence of test schedule on the sleep behavior of undergraduates and its association with performance

Ignacio Estevan 1,*, Romina Sardi 1, Ana Clara Tejera 1, Ana Silva 2, Bettina Tassino 3
Editor: Mohammed Saqr4
PMCID: PMC7946303  PMID: 33690625

Abstract

Sleep is crucial for college students’ well-being. Although recommended sleep duration is between 7–9 hours per day, many students do not sleep that much. Scholar demands are among the causes of observed sleep deprivation in youth. We explored the influence of having a school test on previous night sleep in first-year students and the association of sleep duration and test performance. We ran two surveys in freshman students of the Universidad de la República, Montevideo, Uruguay: 1) 97 students of the School of Sciences who took the test at the same time; and 2) 252 School of Psychology students who took the test in four successive shifts. More than 1/2 of the participants (survey #1) and almost 1/3 (survey #2) reported short regular sleep duration (< 7h). In both samples, the sleep duration of the night before the test was reduced with respect to regular nights (survey #1: 2.1 ± 0.2 h, p < 0.001; survey #2: between 1.7 ± 0.4 h and 3.6 ± 0.3 h, all p < 0.001), with more than 10% of the students who did not sleep at all. In survey 2, sleep duration increased in later shifts (F (3,248) = 4.6, p = 0.004). Using logit regressions, we confirmed that sleep duration was positively related to test scores in both samples (survey #1: exp B = 1.15, p < 0.001; pseudo-R2 = 0.38; survey #2: exp B = 1.03, p < 0.001; pseudo-R2 = 0.25). Delaying test start time may prevent the reduction in sleep duration, which may also improve school performance. In addition, educational policies should include information for students about the impact of sleep on learning and of the consequences of reduced sleep duration.

Introduction

There is a consensus that adults should sleep between 7–9 hours per day [1, 2]. Chronic short sleep duration is associated with an increase in several risk factors [3], and with an increase in the relative risk for multiple-cause mortality [4]. However, according to the Centers for Disease Control and Prevention [5], more than 30% of American young adults report short sleep duration (i.e. < 7h), and a recent meta-analysis showed a mean sleep duration among medical undergraduate students of 6.3 h per night [6].

It is well documented that biological and psycho-social changes during adolescence along with social pressures strongly influence high-school students’ short sleep duration [7–9]. In particular, the compromise between the natural trend of adolescents towards Eveningness and their early school schedule has been pointed out as a key factor affecting sleep duration and quality [10, 11]. Young college undergraduate students still exhibit a delayed chronotype [12], and display a shorter sleep duration when attending morning classes with respect to evening classes [13].

Sleep is related to students’ well-being and mental health [14–17]. Moreover, students’ sleep duration, sleep pattern, and daytime sleepiness have been proved to affect their academic performance [18–21]. Comparing sleep problems to other factors influencing academic performance, Hartman & Prichard [22] found that sleep problems have similar influence in school retention and grades than other factors that receive more attention such as binge drinking or drug consumption.

Despite the relevance of sufficient sleep duration, there is some evidence that students reduce their sleep during exam periods and the night before a test [23]. An actigraphy study with final-year high school students showed a reduction in sleep duration, quality, and efficiency [24]. It has been interpreted that the increase in psychological distress and anxiety typical of exams periods affect both sleep duration and quality [23–27]. In addition to anxiety, using a survey with undergraduate students, Hartwig & Dunlosky [28] showed that more than half the participants often do all their study in one session previous to the test, and most of them also “cram” lots of information in this previous night sacrificing sleep hours with no benefits in their performance. In a study with American college students, almost 60% of them reported engaging at least once in all-night study sessions, which hampered their test performance [29]. Orzerch et al. [30] also found better grades among students not reporting all-night study sessions. However, other studies did not find an association between long night study sessions and test scores [31, 32].

Although the positive association of sleep duration and academic performance seems to be well established, the influence of tests on sleep is not yet fully understood, and studies about the consequences of an acute sleep reduction previous to a test are scarce. In this study, we took advantage of the highly populated freshman University courses of the Universidad de la República, Uruguay, that require students to take tests in different shifts. We aimed to clarify how students modify their sleep habits the night before they take a test and to evaluate the association between sleep duration and academic performance.

Materials and methods

We ran two surveys in freshman students of the Universidad de la República, Montevideo, Uruguay. We used a short computer-based questionnaire to ask about students’ sleep pattern (bedtime, sleep latency, sleep end) on regular nights and the night before a mid-term test that was applied immediately after students finished the test. Questionnaire also included some items about socio-demographic information.

Statistical analyses were performed in R [33] using RStudio as an integrated development environment [34]. Throughout the text sample statistics are reported as Mean ± Standard Deviation, while estimated differences are reported as Mean ± Standard Error. All procedures were approved by the Ethics Committee of the School of Psychology, Universidad de la República, and complied with the principles outlined by the Declaration of Helsinki [35]. All participants gave their informed consent to participate using a digital form.

Survey #1

Undergraduate students of the first year semi-annual course of General Biology of the School of Sciences, Universidad de la República, were invited to participate in this study after finishing the mid-term test in May 2019. Ninety seven students agreed to participate (Table 1), representing the 33.5% of the students who took the test. The number of correct answers for each participant in the 20 multiple-choice questions test was provided by the course teachers. Test score represent 1/3 of the final grade.

Table 1. Characteristics of the participants of both studies.

Total Males Females Age Regular sleep duration Sleep duration before test All-nighters Correct answer rate
Survey #1: School of Science
9:00 to 10:30 97 34 (35.1%) 63 (64.9%) 21.0 ± 5.9 6.6 ± 1.5 4.5 ± 2.4 13 (13.4%) 0.67 ± 0.20a
Survey #2: School of Psychology
8:00 to 9:15 71 10 (14.1%) 61 (85.9%) 23.3 ± 7.3 7.7 ± 1.6 4.1 ± 2.4 12 (16.9%) 0.60 ± 0.12b
9:45 to 11:00 71 7 (9.9%) 64 (90.1%) 25.0 ± 7.9 7.9 ± 1.7 4.9 ± 2.5 9 (12.7%) 0.64 ± 0.15b
11:30 to 12:45 62 9 (14.5%) 53 (85.5%) 22.7 ± 6.8 7.4 ± 1.5 5.1 ± 2.8 11 (17.7%) 0.65 ± 0.11b
13:15 to 14:30 48 6 (12.5%) 42 (87.5%) 24.4 ± 8.8 7.7 ± 1.9 6.0 ± 2.5 5 (10.4%) 0.68 ± 0.13b
Open in a new tab

Note: In each case, time of test attendance is indicated. Discrete variables are presented as Number (Percentage); numeric variables are presented as Mean ± Standard Deviation.

a Test consisted of 20 multiple choice questions.

b Test consisted of 60 true/false questions.

Survey #2

Undergraduate students of the Psychology School, Universidad de la República, who took the mid-term test of Neurobiology course in June 2019 were invited to participate in this study. Neurobiology is a first year semiannual course, and almost 2200 students (74.2% females) began their grade studies in Psychology in 2019 [36]. As 1358 students took the test, they were randomly distributed in four different shifts (see schedule in Table 1). Each one of the four test versions consisted of 60 similar true/false questions. Two hundred fifty two students agreed to participate (Table 1), representing the 18.6% of the students who took the test. In survey #2, a question inquiring about the total time spent studying previous to the test was added (“How many hours do you spend studying adding up yesterday and today hours previous to the test?”). The number of correct answers of each participant was provided by the course teachers. Test score represent 1/2 of the final grade.

Results

Survey #1 sample was sex-biased towards females among participants (Table 1; χ2 = 8.7, p = 0.003). Mean age was 21.0 ± 5.9. Regular reported sleep duration was 6.6 ± 1.5 h, and most participants reported regular sleep duration < 7h (56.7%). Sleep duration and pattern were modified the night before taking the General Biology test (Table 1, Fig 1A). Sleep duration was reduced in 2.1 ± 0.2 h (paired-samples t-test = 9.4, p < 0.001), with 13 students (13.4%) being all-nighters. There was a moderate correlation between regular sleep duration and sleep duration before the test (r = 0.40, p < 0.001). Among sleepers, sleep onset was delayed in 1.0 ± 0.2 h (paired-samples t-test = 6.2, p < 0.001), and sleep end was advanced in 0.5 ± 0.1 h (paired t = 4.1, p < 0.001). The delay in sleep onset was generated by an estimated delay of 1.1 ± 0.2 h in the bedtime (paired-samples t-test = -7.5, p < 0.001), while sleep latency remained unchanged (paired-samples t-test = 0.0, p = 1.0). A logit regression was used to study the association between the correct answer rate and sleep duration. Regular sleep was associated with the ratio of correct answers, and an hour increase in sleep duration was associated with a 10.8% increase in the odds ratio of correct answers (z = 3.3, p < 0.001; Cragg-Uhler pseudo-R2 = 0.11). Sleep duration before the test was also a significant predictor, and an hour increase in sleep duration was associated with a 15.0% increase in the odds ratio of correct answers (z = 6.8, p < 0.001; Cragg-Uhler pseudo-R2 = 0.38). The predicted correct answer rate was 52.3% for an all-nighter and 77.1% for a student who slept 8 h.

Fig 1.

Fig 1

Open in a new tab

Sleep pattern among students that reported sleeping before the test from a) School of Science (survey #1); b) four test shifts in School of Psychology (survey #2).

Sleep patterns are represented from Mean sleep onset to Mean sleep end (red lines represent the Standard Deviation) for regular-days sleep (red) and for the night before the test (white). Gray and white areas indicate photoperiod calculated from sunrise and sunset on the day before the test. Start time of the test is indicated below.

Survey #2 sample was also biased towards females (87.3%; χ2 = 140.3, p < 0.001), across shifts (χ2 = 0.8, p = 0.8). Mean age was 23.8 ± 7.7 years. Mean sleep duration on regular nights was 7.7 ± 1.6 h, with no differences between shifts (F (3,248) = 1.1, p = 0.4; Table 1). Among participants, 31.7% reported short regular sleep duration (< 7 h), with no difference between shifts (χ2 = 5.3, p = 0.15). Regular sleep pattern was also similar between shifts (mean sleep onset was 0:29 ± 1:23; mean sleep end was 8:10 ± 1:36), as no difference was found in either sleep onset (F (3,248) = 0.2, p = 0.9, Fig 1B) or sleep end (F (3,248) = 0.7, p = 0.5, Fig 1B). The night before the test sleep duration was reduced: sleep in 8:00 shift was reduced in 3.6 ± 0.3 h (paired-samples t-test = 10.9, p < 0.001), in 9:45 shift sleep was reduced in 3.0 ± 0.3 h (paired-samples t-test = 9.1, p < 0.001), in 11:30 shift was reduced in 2.3 ± 0.4 h (paired-samples t-test = 6.6, p < 0.001), and in 13:15 shift reduction was in 1.7 ± 0.4 h (paired-samples t-test = 4.3, p < 0.001). A small correlation between regular sleep duration and sleep duration before was observed (r = 0.09, p = 0.032). Sleep duration before the test was different between test shifts (F (3,248) = 4.6, p = 0.004; Table 1), as last shift students slept more than the first shift students (Tukey post-hoc t = -3.8, p < 0.001). All-nighters were 14.7% of participants, with no difference between test shifts (χ2 = 1.7, p = 0.64). Moreover, sleep reduction was different between test shifts (F (3,248) = 4.9, p = 0.002), and Tukey post-hoc test showed significant differences between students in 8:00 vs 11:30 shift (t = 2.6, p = 0.048), and between students in 8:00 vs 13:15 shift (t = 3.6, p = 0.003). Sleep pattern was also modified the night before the test (Fig 1B). Sleep onset the night before the test was similar between test shifts (F (3,211) = 0.9, p = 0.7), and was delayed compared to regular nights an estimated 1.3 ± 0.1 h (paired-samples t-test = -12.6, p < 0.001), with no difference between shifts (F (3,211) = 0.5, p = 0.7). This delay in sleep onset emerged from a delay in the bedtime of 1.3 ± 0.1 h (paired-samples t-test = -11.9, p < 0.001), similar between shifts (F (3,211) = 0.6, p = 0.6), as no difference was observed in the sleep latency compared to regular days (paired-samples t-test = -0.5, p = 0.6). Sleep end was dependent on the test start time (F (3,211) = 39.0, p < 0.001; Fig 1B): Sleep end was delayed as test start later with all Tukey post-hoc paired comparisons significant (all p < 0.035). Sleep end difference between regular nights and the night before the test varied with test shift (F (3,211) = 18.2, p <0.001): Sleep end was advanced 1.6 ± 0.2 h when test started at 8:00 (paired-samples t-test = 8.0, p < 0.001) and 1.1 ± 0.2 h when test started at 9:45 (paired-samples t-test = 5.3, p < 0.001), while no difference was observed in the other two shifts.

The association between the correct answer rate with the sleep duration and the test shift was studied using a logit regression model. Regular sleep duration did not predict test performance (z = -1.45, p = 0.15). However, an hour increase in sleep duration before the test was associated with a 3.8% increase in the odds ratio of correct answers (z = 5.7, p < 0.001; Cragg-Uhler pseudo-R2 = 0.12). When the test shift was added it resulted in a significant predictor and model fit increased (Cragg-Uhler pseudo-R2 = 0.25). Paired comparisons using Tukey adjustment showed a significant increase in the odd of correct answers in 9:45 shift (19.9%, z = 4.1, p < 0.001), 11:30 shift (22.3%, z = 4.3, p = 0.001) and 13:15 shift (36.3%, z = 5.9, p < 0.001) compared to 8:00 shift. The predicted correct answer rate was 56.7% for an all-nighter who attended the first shift and 69.0% for a student who slept 8 h and attended the fourth shift. Mean number of hours spent studying before the test was 8.0 ± 5.0 h, with no difference between test shifts (F (3, 248) = 2.25, p = 0.08). Number of hours spent studying did not correlate with sleep before the test (r = -0.10, p = 0.3) nor with test performance (r = 0.03, p = 0.6).

Discussion

In this study, we present data to evaluate the influence of tests on freshman college students’ sleep behavior and the influence of sleep on their academic performance. Although these issues have been addressed in previous reports [23, 24, 31, 32], this is the first study to explore how sleep patterns of the night before the test change when the test is taken at different times (survey #2). Overall (survey #1 and #2), most students delayed their bedtime the night before the test, reducing their sleep duration, and more than 10% did not even sleep at all the night before. Even when the test started as late as 13:15, the sleep duration of the night before was shorter than in regular nights, and 10% of the students stayed awake all night. In addition, sleep duration was positively correlated with the number of correct answers in the test, and therefore with school grades. When analyzing these effects across shifts (survey #2), we found that sleep duration and academic performance improved as test start times were delayed.

High rate of short regular sleep was found in both surveys, with more than 1/2 (survey #1) and almost 1/3 of students (survey #2) who reported sleep duration <7 h in average per night. The rate of students with short regular sleep was higher and mean sleep duration was shorter in students of School of Science (survey #1) than in students of the Psychology School (survey #2), probably because the former were younger than the latter [37]. Similar values of sleep deprivation were previously reported in Uruguayan university students [38], and this should be a matter of concern based on the multiple consequences of chronic inadequate sleep [14–17].

Taking the test had a strong influence in the night before sleep behavior of students, a pattern that has been previously described using both actigraphy data and questionnaires in young students [23, 24]. As stated by Hartwig & Dunlosky [28], sleep reduction seems to be a consequence of giving up hours of sleep to obtain more study hours prior to the test. We confirmed this general pattern in the present study as students of both surveys delayed their time to go to bed the night before the test in about 1 h, regardless of test start times.

Several previous studies reported a positive association between regular sleep duration and grades [32, 39–42], while others highlight the importance of regular sleep quality, rather than duration, on academic performance [39, 40, 43, 44]. We observed an association of regular sleep duration and test performance only in survey #1, as the odds ratio of correct answers increased with sleep duration. Sleep duration on the night before the test did predict test performance in survey #2, and was a better predictor of performance in survey #1 compared to regular sleep. In Uruguay, grades use a non-linear scale from 0 to 12. The fair lowest passing grade is 3 and corresponds to 60% achievement, while 90% achievement corresponds to grade 10. This complexity of the Uruguayan grading system prevented us from using grades in regressions. However, in both surveys when predicted correct answer rate was converted to grades 8 h-sleepers obtained a passing grade while all-nighters did not. Scullin [45] found a similar result using actigraphy data and showing that long-sleep students outperform short-sleep students in tests scores. The difference between surveys in regression coefficients and explained deviance may be related with the different type of questions (true/false vs multiple choice) employed in both courses, as the probability of answering correctly at random is higher in true-false type questions.

School and test shifts, an obligated solution to the insufficient universities’ infrastructure to deal with the progressively increasing number of students in many countries [46], can also be seen as an opportunistic tool to deepen the study of the influence of test start time on sleep and performance [47–49]. In survey #2, we found that the sleep duration of the night before the test increased as test start time was delayed. A previous study in Brazilian undergraduate students attending school in different shifts found a similar pattern [13]: sleep duration was longer in students of the afternoon-shift with respect to morning-shift ones. We also found that students’ performance was significantly higher in later shifts with respect to early ones. The enhanced performance of late-shift students is more likely due to their longer sleep duration and not to the time spent studying the day before the test, which was not significantly different across shifts. In addition to longer sleep durations, chronotype-associated differences in performance may also contribute to the differences observed between shifts [50, 51]. To address this issue in the future, we plan to add the assessment of Morningness-Eveningness in students of the Psychology School taking tests in different shifts.

Our study has several limitations. Self-report questionnaires may overestimate sleep duration compared to objective measures [52], and short sleep prevalence may be even higher than reported among Uruguayan college students. Although data were collected immediately after the test to prevent memory blurring, future studies should include more objective measures to confirm our results. A previous study using actigraphy data found a similar pattern of sleep reduction during exam period [45]. Sleep disturbance and reduced performance may be both associated with the high levels of anxiety prior to a test [53]. However, we did not observe an increase in sleep latency before the test, a measure that has been related to anxiety levels [14, 54]. Nevertheless, the analysis of personality-linked variables could help to get a better understanding of the interaction between students’ sleep behavior and study practice before a test.

In this study, we show that many college students reported not getting enough sleep. In addition, we found that taking a test influences students’ sleep behavior, and that the sleep duration of the night before the test is associated with test performance. Given the relevance of adequate sleep, it appears as a cost-efficient way to improve student’s academic performance and well-being [21, 55]. Although delaying school (and tests) start times has been related to longer sleep duration and better academic performance, it seems not enough. These evidence should inspire educational policies and promote an open communication of the impact of sleep on learning and of the consequences of reduced sleep duration.

Acknowledgments

We thank everyone who participated in this study. We thank Álvaro Cabana for his suggestions for analysis.

Data Availability

Data are available from the project Open Science Framework database (https://osf.io/g7xfw/).

Funding Statement

IE was supported by a 2020-2023 Scholarship from Comisión Académica de Posgrado, Universidad de la República, Uruguay. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.

References

  • 1.Watson NF, Badr MS, Belenky G, Bliwise DL, Buxton OM, Buysse D, et al. Recommended amount of sleep for a healthy adult: A joint consensus statement of the American Academy of Sleep Medicine and Sleep Research Society. J. Clin. Sleep Med. 2015;11:591–2. 10.5664/jcsm.4758 [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 2.Watson NF, Badr MS, Belenky G, Bliwise DL, Buxton OM, Buysse D, et al. Joint consensus statement of the American Academy of Sleep Medicine and Sleep Research Society on the recommended amount of sleep for a healthy adult: Methodology and discussion. Sleep 2015;38:1161–83. 10.5665/sleep.4886 [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 3.Itani O, Jike M, Watanabe N, Kaneita Y. Short sleep duration and health outcomes: a systematic review, meta-analysis, and meta-regression. Sleep Med. 2017;32:246–56. 10.1016/j.sleep.2016.08.006 [DOI] [PubMed] [Google Scholar]
  • 4.Gallicchio L, Kalesan B. Sleep duration and mortality: A systematic review and meta-analysis. J. Sleep Res. 2009;18:148–58. 10.1111/j.1365-2869.2008.00732.x [DOI] [PubMed] [Google Scholar]
  • 5.Centers for Disease Control and Prevention. Sleep and sleep disorders [Internet]. 2017 [cited 2020 Apr 17];Available from: https://www.cdc.gov/sleep/data_statistics.html
  • 6.Jahrami H, Dewald-Kaufmann J, Faris sMA-I, AlAnsari AMS, Taha M, AlAnsari N. Prevalence of sleep problems among medical students: A systematic review and meta-analysis. J. Public Health Berl. [Internet] 2019;Available from: 10.1007/s10389-019-01064-6 [DOI] [Google Scholar]
  • 7.Owens JA, Adolescent Sleep Working Group, Committee on Adolescence. Insufficient sleep in adolescents and young adults: An update on causes and consequences. Pediatrics 2014;134:e921–32. 10.1542/peds.2014-1696 [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 8.Crowley SJ, Wolfson AR, Tarokh L, Carskadon MA. An update on adolescent sleep: New evidence informing the perfect storm model. J. Adolesc. 2018;67:55–65. 10.1016/j.adolescence.2018.06.001 [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 9.Carskadon MA. Sleep in adolescents: the perfect storm. Pediatr. Clin. North Am. 2011;58:637–47. 10.1016/j.pcl.2011.03.003 [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 10.Gradisar M, Gardner G, Dohnt H. Recent worldwide sleep patterns and problems during adolescence: A review and meta-analysis of age, region, and sleep. Sleep Med. 2011;12:110–8. 10.1016/j.sleep.2010.11.008 [DOI] [PubMed] [Google Scholar]
  • 11.Tarokh L, Short M, Crowley SJ, Fontanellaz-Castiglione CEG, Carskadon MA. Sleep and circadian rhythms in adolescence. Curr. Sleep Med. Rep. 2019;5:181–92. [Google Scholar]
  • 12.Roenneberg T, Kuehnle T, Pramstaller PP, Ricken J, Havel M, Guth A, et al. A marker for the end of adolescence. Curr. Biol. 2004;14:R1038–9. 10.1016/j.cub.2004.11.039 [DOI] [PubMed] [Google Scholar]
  • 13.Machado ERS, Varella VBR, Andrade MMM. The influence of study schedules and work on the sleep–wake cycle of college students. Biol. Rhythm Res. 1998;29:578–84. [Google Scholar]
  • 14.Becker SP, Jarrett MA, Luebbe AM, Garner AA, Burns GL, Kofler MJ. Sleep in a large, multi-university sample of college students: Sleep problem prevalence, sex differences, and mental health correlates. Sleep Health 2018;4:174–81. 10.1016/j.sleh.2018.01.001 [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 15.Lemma S, Gelaye B, Berhane Y, Worku A, Williams MA. Sleep quality and its psychological correlates among university students in Ethiopia: A cross-sectional study. BMC Psychiatry 2012;12:237. 10.1186/1471-244X-12-237 [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 16.Boehm MA, Lei QM, Lloyd RM, Prichard JR. Depression, anxiety, and tobacco use: Overlapping impediments to sleep in a national sample of college students. J. Am. Coll. Health 2016;64:565–74. 10.1080/07448481.2016.1205073 [DOI] [PubMed] [Google Scholar]
  • 17.Norbury R, Evans S. Time to think: Subjective sleep quality, trait anxiety and university start time. Psychiatry Res. 2019;271:214–9. 10.1016/j.psychres.2018.11.054 [DOI] [PubMed] [Google Scholar]
  • 18.Gomez Fonseca A, Genzel L. Sleep and academic performance: Considering amount, quality and timing. Curr. Opin. Behav. Sci. 2020;33:65–71. [Google Scholar]
  • 19.Hershner S. Sleep and academic performance: Measuring the impact of sleep. Curr. Opin. Behav. Sci. 2020;33:51–6. [Google Scholar]
  • 20.Hershner S, Chervin R. Causes and consequences of sleepiness among college students. Nat. Sci. Sleep 2014;6:73–84. 10.2147/NSS.S62907 [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 21.Prichard JR. Sleep predicts collegiate academic performance: Implications for equity in student retention and success. Sleep Med. Clin. 2020;15:59–69. 10.1016/j.jsmc.2019.10.003 [DOI] [PubMed] [Google Scholar]
  • 22.Hartmann ME, Prichard JR. Calculating the contribution of sleep problems to undergraduates’ academic success. Sleep Health 2018;4:463–71. 10.1016/j.sleh.2018.07.002 [DOI] [PubMed] [Google Scholar]
  • 23.Zunhammer M, Eichhammer P, Busch V. Sleep quality during exam stress: The role of alcohol, caffeine and nicotine. PLOS ONE 2014;9:e109490. 10.1371/journal.pone.0109490 [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 24.Astill RG, Verhoeven D, Vijzelaar RL, Van Someren EJW. Chronic stress undermines the compensatory sleep efficiency increase in response to sleep restriction in adolescents. J. Sleep Res. 2013;22:373–9. 10.1111/jsr.12032 [DOI] [PubMed] [Google Scholar]
  • 25.Lund HG, Reider BD, Whiting AB, Prichard JR. Sleep patterns and predictors of disturbed sleep in a large population of college students. J. Adolesc. Health 2010;46:124–32. 10.1016/j.jadohealth.2009.06.016 [DOI] [PubMed] [Google Scholar]
  • 26.Mesquita G, Reimão R. Stress and sleep quality in high school Brazilian adolescents. An. Acad. Bras. Ciênc. 2010;82:545–51. 10.1590/s0001-37652010000200029 [DOI] [PubMed] [Google Scholar]
  • 27.Seun-Fadipe CT, Mosaku KS. Sleep quality and psychological distress among undergraduate students of a Nigerian university. Sleep Health 2017;3:190–4. 10.1016/j.sleh.2017.02.004 [DOI] [PubMed] [Google Scholar]
  • 28.Hartwig MK, Dunlosky J. Study strategies of college students: Are self-testing and scheduling related to achievement? Psychon. Bull. Rev. 2012;19:126–34. 10.3758/s13423-011-0181-y [DOI] [PubMed] [Google Scholar]
  • 29.Thacher PV. University students and the “all nighter”: Correlates and patterns of students’ engagement in a single night of total sleep deprivation. Behav. Sleep. Med. 2008;6:16–31. 10.1080/15402000701796114 [DOI] [PubMed] [Google Scholar]
  • 30.Orzech KM, Salafsky DB, Hamilton LA. The state of sleep among college students at a large public university. J. Am. Coll. Health 2011;59:612–9. 10.1080/07448481.2010.520051 [DOI] [PubMed] [Google Scholar]
  • 31.Engle-Friedman M. Self-imposed sleep loss, sleepiness, effort and performance. Sleep Hypn. 2004;6:155–62. [Google Scholar]
  • 32.Okano K, Kaczmarzyk JR, Dave N, Gabrieli JDE, Grossman JC. Sleep quality, duration, and consistency are associated with better academic performance in college students. Npj Sci. Learn. 2019;4:1–5. 10.1038/s41539-019-0040-6 [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 33.R Core Team. R: A language and environment for statistical computing [Internet]. Vienna, Austria: R Foundation for Statistical Computing; 2019. Available from: https://www.R-project.org/ [Google Scholar]
  • 34.RStudio Team. RStudio: Integrated development environment for R [Internet]. Boston, MA: RStudio, Inc.; 2016. Available from: http://www.rstudio.com/ [Google Scholar]
  • 35.World Medical Association. World Medical Association declaration of Helsinki: Ethical principles for medical research involving human subjects. JAMA 2013;310:2191–4. 10.1001/jama.2013.281053 [DOI] [PubMed] [Google Scholar]
  • 36.PRORREN. Informe generación de ingreso 2019. Licenciatura en Psicología, Udelar [Internet]. Montevideo: Facultad de Psicología; 2020. [cited 2019 Dec 17]. Available from: https://psico.edu.uy/sites/default/pub_files/2019-11/-Informe%20Gen%202019%20%283%29.pdf [Google Scholar]
  • 37.Ohayon MM, Carskadon MA, Guilleminault C, Vitiello MV. Meta-analysis of quantitative sleep parameters from childhood to old age in healthy individuals: developing normative sleep values across the human lifespan. Sleep 2004;27:1255–74. 10.1093/sleep/27.7.1255 [DOI] [PubMed] [Google Scholar]
  • 38.Tassino B, Horta S, Santana N, Levandovski R, Silva A. Extreme late chronotypes and social jetlag challenged by Antarctic conditions in a population of university students from Uruguay. Sleep Sci. 2016;9:20–8. 10.1016/j.slsci.2016.01.002 [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 39.Gaultney JF. The prevalence of sleep disorders in college students: Impact on academic performance. J. Am. Coll. Health 2010;59:91–7. 10.1080/07448481.2010.483708 [DOI] [PubMed] [Google Scholar]
  • 40.Gilbert SP, Weaver CC. Sleep quality and academic performance in university students: A wake-up call for college psychologists. J. Coll. Stud. Psychother. 2010;24:295–306. [Google Scholar]
  • 41.Medeiros ALD, Mendes DB, Lima PF, Araujo JF. The relationships between sleep-wake cycle and academic performance in medical students. Biol. Rhythm Res. 2001;32:263–70. [Google Scholar]
  • 42.Taylor DJ, Vatthauer KE, Bramoweth AD, Ruggero C, Roane B. The role of sleep in predicting college academic performance: Is it a unique predictor? Behav. Sleep. Med. 2013;11:159–72. 10.1080/15402002.2011.602776 [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 43.Gomes AA, Tavares J, de Azevedo MHP. Sleep and academic performance in undergraduates: A multi-measure, multi-predictor approach. Chronobiol. Int. 2011;28:786–801. 10.3109/07420528.2011.606518 [DOI] [PubMed] [Google Scholar]
  • 44.Piro RS, Alhakem SSM, Azzez SS, Abdulah DM. Prevalence of sleep disorders and their impact on academic performance in medical students/University of Duhok. Sleep Biol. Rhythms 2018;16:125–32. [Google Scholar]
  • 45.Scullin MK. The eight hour sleep challenge during final exams week. Teach. Psychol. 2019;46:55–63. [Google Scholar]
  • 46.Bray M. Double-shift schooling: design and operation for cost-effectiveness. 3rd ed. Paris: UNESCO; 2008. [Google Scholar]
  • 47.Estevan I, Silva A, Tassino B. School start times matter, eveningness does not. Chronobiol. Int. 2018;35:1753–7. 10.1080/07420528.2018.1504785 [DOI] [PubMed] [Google Scholar]
  • 48.Goldin AP, Sigman M, Braier G, Golombek DA, Leone MJ. Interplay of chronotype and school timing predicts school performance. Nat. Hum. Behav. 2020;4:1–10. 10.1038/s41562-020-0818-9 [DOI] [PubMed] [Google Scholar]
  • 49.Arrona-Palacios A, Díaz-Morales JF. Morningness-eveningness is not associated with academic performance in the afternoon school shift: Preliminary findings. Br. J. Educ. Psychol. 2017;88:480–98. 10.1111/bjep.12196 [DOI] [PubMed] [Google Scholar]
  • 50.Borisenkov MF, Perminova EV, Kosova AL. Chronotype, sleep length, and school achievement of 11- to 23-year-old students in northern european russia. Chronobiol. Int. 2010;27:1259–70. 10.3109/07420528.2010.487624 [DOI] [PubMed] [Google Scholar]
  • 51.Eliasson AH, Lettieri CJ, Eliasson AH. Early to bed, early to rise! Sleep habits and academic performance in college students. Sleep Breath. 2010;14:71–5. 10.1007/s11325-009-0282-2 [DOI] [PubMed] [Google Scholar]
  • 52.Lauderdale DS, Knutson KL, Yan LL, Liu K, Rathouz PJ. Self-reported and measured sleep duration: How similar are they? Epidemiology 2008;19:838–45. 10.1097/EDE.0b013e318187a7b0 [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 53.Blankstein KR, Flett GL, Watson MS, Koledin S. Test anxiety, self-evaluative worry, and sleep disturbance in college students. Anxiety Res. 1990;3:193–204. [Google Scholar]
  • 54.Papadimitriou GN, Linkowski P. Sleep disturbance in anxiety disorders. Int. Rev. Psychiatry 2005;17:229–36. 10.1080/09540260500104524 [DOI] [PubMed] [Google Scholar]
  • 55.Prichard JR, Hartmann ME. Follow-up to Hartmann & Prichard: Should universities invest in promoting healthy sleep? A question of academic and economic significance. Sleep Health 2019;5:320–5. 10.1016/j.sleh.2019.01.006 [DOI] [PubMed] [Google Scholar]

Decision Letter 0

Mohammed Saqr

27 Nov 2020

PONE-D-20-18113

Should I study or should I sleep?

PLOS ONE

Dear Dr. Estevan,

Thank you for submitting your manuscript to PLOS ONE. After careful consideration, we feel that it has merit but does not fully meet PLOS ONE’s publication criteria as it currently stands. Therefore, we invite you to submit a revised version of the manuscript that addresses the points raised during the review process. The reviewers has raised some concerns especially regarding the effect size and its significance which we wish to address in the revised version.

Please submit your revised manuscript by Jan 11 2021 11:59PM. If you will need more time than this to complete your revisions, please reply to this message or contact the journal office at plosone@plos.org. When you're ready to submit your revision, log on to https://www.editorialmanager.com/pone/ and select the 'Submissions Needing Revision' folder to locate your manuscript file.

Please include the following items when submitting your revised manuscript:

  • A rebuttal letter that responds to each point raised by the academic editor and reviewer(s). You should upload this letter as a separate file labeled 'Response to Reviewers'.

  • A marked-up copy of your manuscript that highlights changes made to the original version. You should upload this as a separate file labeled 'Revised Manuscript with Track Changes'.

  • An unmarked version of your revised paper without tracked changes. You should upload this as a separate file labeled 'Manuscript'.

If you would like to make changes to your financial disclosure, please include your updated statement in your cover letter. Guidelines for resubmitting your figure files are available below the reviewer comments at the end of this letter.

If applicable, we recommend that you deposit your laboratory protocols in protocols.io to enhance the reproducibility of your results. Protocols.io assigns your protocol its own identifier (DOI) so that it can be cited independently in the future. For instructions see: http://journals.plos.org/plosone/s/submission-guidelines#loc-laboratory-protocols

We look forward to receiving your revised manuscript.

Kind regards,

Mohammed Saqr, Ph.D

Academic Editor

PLOS ONE

Journal Requirements:

When submitting your revision, we need you to address these additional requirements.

1. Please ensure that your manuscript meets PLOS ONE's style requirements, including those for file naming. The PLOS ONE style templates can be found at

https://journals.plos.org/plosone/s/file?id=wjVg/PLOSOne_formatting_sample_main_body.pdf and

https://journals.plos.org/plosone/s/file?id=ba62/PLOSOne_formatting_sample_title_authors_affiliations.pdf

2. Please consider changing the title so as to meet our title format requirement (https://journals.plos.org/plosone/s/submission-guidelines). In particular, the title should be "Specific, descriptive, concise, and comprehensible to readers outside the field" and in this case it is not informative and specific about your study's scope and methodology.

3. Please clarify (on line 228) whether you can conclude about students' lack of sleep or their reported lack of sleep.

4. Please provide additional details regarding participant consent. In the ethics statement in the Methods and online submission information, please ensure that you have specified whether consent was informed.

5. We note that you have stated that you will provide repository information for your data at acceptance. Should your manuscript be accepted for publication, we will hold it until you provide the relevant accession numbers or DOIs necessary to access your data. If you wish to make changes to your Data Availability statement, please describe these changes in your cover letter and we will update your Data Availability statement to reflect the information you provide.

[Note: HTML markup is below. Please do not edit.]

Reviewers' comments:

Reviewer's Responses to Questions

Comments to the Author

1. Is the manuscript technically sound, and do the data support the conclusions?

The manuscript must describe a technically sound piece of scientific research with data that supports the conclusions. Experiments must have been conducted rigorously, with appropriate controls, replication, and sample sizes. The conclusions must be drawn appropriately based on the data presented.

Reviewer #1: Yes

Reviewer #2: Yes

**********

2. Has the statistical analysis been performed appropriately and rigorously?

Reviewer #1: Yes

Reviewer #2: I Don't Know

**********

3. Have the authors made all data underlying the findings in their manuscript fully available?

The PLOS Data policy requires authors to make all data underlying the findings described in their manuscript fully available without restriction, with rare exception (please refer to the Data Availability Statement in the manuscript PDF file). The data should be provided as part of the manuscript or its supporting information, or deposited to a public repository. For example, in addition to summary statistics, the data points behind means, medians and variance measures should be available. If there are restrictions on publicly sharing data—e.g. participant privacy or use of data from a third party—those must be specified.

Reviewer #1: Yes

Reviewer #2: Yes

**********

4. Is the manuscript presented in an intelligible fashion and written in standard English?

PLOS ONE does not copyedit accepted manuscripts, so the language in submitted articles must be clear, correct, and unambiguous. Any typographical or grammatical errors should be corrected at revision, so please note any specific errors here.

Reviewer #1: Yes

Reviewer #2: Yes

**********

5. Review Comments to the Author

Please use the space provided to explain your answers to the questions above. You may also include additional comments for the author, including concerns about dual publication, research ethics, or publication ethics. (Please upload your review as an attachment if it exceeds 20,000 characters)

Reviewer #1: This is an interesting study of university students and their sleep habits prior to a mid-term examination. the authors show that the sleep time the night before an exam is less than their habitual sleep and that grades correlated with the sleep time.

My main concern is that the size of the effect is small; in survey 1, 1 hour more sleep meant 5% increase in correct answers and in survey 1, 1 hour more sleep was only associated with 1.4% increase in correct answers. These numbers may not be significant to change the overall grade for the subject. Do the authors have data instead on whether more students failed if got less sleep? Or if the overall grade (ie, A to B, B to C) was effected because of less sleep?

Lines 185 and 186: not sure that 'short sleep ratio' is previously defined; would find different wording.

Reviewer #2: This is an important topic considered by the authors and studied in an ingenious manner i.e. in the group of students being offered exams in four different shifts. This allows the opportunity to test the effect of sleep duration and timing on outcomes of the test performance.

The manuscript is well written.

**********

6. PLOS authors have the option to publish the peer review history of their article (what does this mean?). If published, this will include your full peer review and any attached files.

If you choose “no”, your identity will remain anonymous but your review may still be made public.

Do you want your identity to be public for this peer review? For information about this choice, including consent withdrawal, please see our Privacy Policy.

Reviewer #1: No

Reviewer #2: No

[NOTE: If reviewer comments were submitted as an attachment file, they will be attached to this email and accessible via the submission site. Please log into your account, locate the manuscript record, and check for the action link "View Attachments". If this link does not appear, there are no attachment files.]

While revising your submission, please upload your figure files to the Preflight Analysis and Conversion Engine (PACE) digital diagnostic tool, https://pacev2.apexcovantage.com/. PACE helps ensure that figures meet PLOS requirements. To use PACE, you must first register as a user. Registration is free. Then, login and navigate to the UPLOAD tab, where you will find detailed instructions on how to use the tool. If you encounter any issues or have any questions when using PACE, please email PLOS at figures@plos.org. Please note that Supporting Information files do not need this step.

PLoS One. 2021 Mar 10;16(3):e0247104. doi: 10.1371/journal.pone.0247104.r002

Author response to Decision Letter 0

22 Dec 2020

Academic Editor

Please ensure that your manuscript meets PLOS ONE's style requirements, including those for file naming.

The manuscript has been revised according to the journal style requirements.

Please consider changing the title so as to meet our title format requirement

We extended the title with a description of the aims of the study.

Please clarify (on line 228) whether you can conclude about students' lack of sleep or their reported lack of sleep.

Thank you for the observation. We modified the expression to better describe our findings (line 241).

Please provide additional details regarding participant consent. In the ethics statement in the Methods and online submission information, please ensure that you have specified whether consent was informed.

The use of informed consent was included in line 90.

We note that you have stated that you will provide repository information for your data at acceptance. Should your manuscript be accepted for publication, we will hold it until you provide the relevant accession numbers or DOIs necessary to access your data.

The information was included in the Cover Letter.

Reviewer #1

My main concern is that the size of the effect is small; in survey 1, 1 hour more sleep meant 5% increase in correct answers and in survey 1, 1 hour more sleep was only associated with 1.4% increase in correct answers. These numbers may not be significant to change the overall grade for the subject. Do the authors have data instead on whether more students failed if got less sleep? Or if the overall grade (ie, A to B, B to C) was effected because of less sleep?

Thank you for this observation. We did again the analyses using logistic regressions to explain the correct answers rate. The results did not change, but these new analyses explain a greater proportion of the deviance, better modeling the association between sleep and performance (lines 124-131 and 168-177 in Results, table 1, and lines 208-211 in Discussion). The abstract was modified accordingly (lines 32-34).

In Uruguay, grades are given in figures on a scale from 0 to 12.The fair lowest passing grade is 3 and corresponds to 60% achievement, while 91% achievement corresponds to grade 10. This complexity of the Uruguayan grading system prevented us from including the grades. Instead, we estimated the correct answer rate for extreme sleep durations of 0h and 8h (lines 130-131 and 176-177). The smaller change in survey #2 is now discussed in lines 213-216.

Lines 185 and 186: not sure that 'short sleep ratio' is previously defined; would find different wording.

The expression was replaced (lines 194-195).

Attachment

Submitted filename: MS.v2-Responses.docx

Click here for additional data file. (14.1KB, docx)

Decision Letter 1

Mohammed Saqr

4 Jan 2021

PONE-D-20-18113R1

Should I study or should I go (to sleep)? The influence of test schedule on the sleep behavior of undergraduates and its association with performance.

PLOS ONE

Dear Dr. Estevan,

Thank you for submitting your manuscript to PLOS ONE. After careful consideration, we feel that it has merit but does not fully meet PLOS ONE’s publication criteria as it currently stands. Therefore, we invite you to submit a revised version of the manuscript that addresses the points raised during the review process. Please amend the discussion with needed explanations.

Please submit your revised manuscript by Feb 18 2021 11:59PM. If you will need more time than this to complete your revisions, please reply to this message or contact the journal office at plosone@plos.org. When you're ready to submit your revision, log on to https://www.editorialmanager.com/pone/ and select the 'Submissions Needing Revision' folder to locate your manuscript file.

Please include the following items when submitting your revised manuscript:

  • A rebuttal letter that responds to each point raised by the academic editor and reviewer(s). You should upload this letter as a separate file labeled 'Response to Reviewers'.

  • A marked-up copy of your manuscript that highlights changes made to the original version. You should upload this as a separate file labeled 'Revised Manuscript with Track Changes'.

  • An unmarked version of your revised paper without tracked changes. You should upload this as a separate file labeled 'Manuscript'.

If you would like to make changes to your financial disclosure, please include your updated statement in your cover letter. Guidelines for resubmitting your figure files are available below the reviewer comments at the end of this letter.

If applicable, we recommend that you deposit your laboratory protocols in protocols.io to enhance the reproducibility of your results. Protocols.io assigns your protocol its own identifier (DOI) so that it can be cited independently in the future. For instructions see: http://journals.plos.org/plosone/s/submission-guidelines#loc-laboratory-protocols

We look forward to receiving your revised manuscript.

Kind regards,

Mohammed Saqr, Ph.D

Academic Editor

PLOS ONE

[Note: HTML markup is below. Please do not edit.]

Reviewers' comments:

Reviewer's Responses to Questions

Comments to the Author

1. If the authors have adequately addressed your comments raised in a previous round of review and you feel that this manuscript is now acceptable for publication, you may indicate that here to bypass the “Comments to the Author” section, enter your conflict of interest statement in the “Confidential to Editor” section, and submit your "Accept" recommendation.

Reviewer #1: All comments have been addressed

**********

2. Is the manuscript technically sound, and do the data support the conclusions?

The manuscript must describe a technically sound piece of scientific research with data that supports the conclusions. Experiments must have been conducted rigorously, with appropriate controls, replication, and sample sizes. The conclusions must be drawn appropriately based on the data presented.

Reviewer #1: Yes

**********

3. Has the statistical analysis been performed appropriately and rigorously?

Reviewer #1: Yes

**********

4. Have the authors made all data underlying the findings in their manuscript fully available?

The PLOS Data policy requires authors to make all data underlying the findings described in their manuscript fully available without restriction, with rare exception (please refer to the Data Availability Statement in the manuscript PDF file). The data should be provided as part of the manuscript or its supporting information, or deposited to a public repository. For example, in addition to summary statistics, the data points behind means, medians and variance measures should be available. If there are restrictions on publicly sharing data—e.g. participant privacy or use of data from a third party—those must be specified.

Reviewer #1: Yes

**********

5. Is the manuscript presented in an intelligible fashion and written in standard English?

PLOS ONE does not copyedit accepted manuscripts, so the language in submitted articles must be clear, correct, and unambiguous. Any typographical or grammatical errors should be corrected at revision, so please note any specific errors here.

Reviewer #1: Yes

**********

6. Review Comments to the Author

Please use the space provided to explain your answers to the questions above. You may also include additional comments for the author, including concerns about dual publication, research ethics, or publication ethics. (Please upload your review as an attachment if it exceeds 20,000 characters)

Reviewer #1: The authors have better explained the grading system in Uruguay and why they cannot provide 'grades' per se. This explanation would also be helpful to other readers and therefore my final recommendation is that the sentences written to me about grading be added to the Discussion. I think important as clearly the predicted grades on line 131 represent 'failure' v. 'passing.'

**********

7. PLOS authors have the option to publish the peer review history of their article (what does this mean?). If published, this will include your full peer review and any attached files.

If you choose “no”, your identity will remain anonymous but your review may still be made public.

Do you want your identity to be public for this peer review? For information about this choice, including consent withdrawal, please see our Privacy Policy.

Reviewer #1: No

[NOTE: If reviewer comments were submitted as an attachment file, they will be attached to this email and accessible via the submission site. Please log into your account, locate the manuscript record, and check for the action link "View Attachments". If this link does not appear, there are no attachment files.]

While revising your submission, please upload your figure files to the Preflight Analysis and Conversion Engine (PACE) digital diagnostic tool, https://pacev2.apexcovantage.com/. PACE helps ensure that figures meet PLOS requirements. To use PACE, you must first register as a user. Registration is free. Then, login and navigate to the UPLOAD tab, where you will find detailed instructions on how to use the tool. If you encounter any issues or have any questions when using PACE, please email PLOS at figures@plos.org. Please note that Supporting Information files do not need this step.

Decision Letter 2

Mohammed Saqr

2 Feb 2021

Should I study or should I go (to sleep)? The influence of test schedule on the sleep behavior of undergraduates and its association with performance.

PONE-D-20-18113R2

Dear Dr. Estevan,

We’re pleased to inform you that your manuscript has been judged scientifically suitable for publication and will be formally accepted for publication once it meets all outstanding technical requirements.

Within one week, you’ll receive an e-mail detailing the required amendments. When these have been addressed, you’ll receive a formal acceptance letter and your manuscript will be scheduled for publication.

An invoice for payment will follow shortly after the formal acceptance. To ensure an efficient process, please log into Editorial Manager at http://www.editorialmanager.com/pone/, click the 'Update My Information' link at the top of the page, and double check that your user information is up-to-date. If you have any billing related questions, please contact our Author Billing department directly at authorbilling@plos.org.

If your institution or institutions have a press office, please notify them about your upcoming paper to help maximize its impact. If they’ll be preparing press materials, please inform our press team as soon as possible -- no later than 48 hours after receiving the formal acceptance. Your manuscript will remain under strict press embargo until 2 pm Eastern Time on the date of publication. For more information, please contact onepress@plos.org.

Kind regards,

Mohammed Saqr, Ph.D

Academic Editor

PLOS ONE

Acceptance letter

Mohammed Saqr

15 Feb 2021

PONE-D-20-18113R2

Should I study or should I go (to sleep)? The influence of test schedule on the sleep behavior of undergraduates and its association with performance.

Dear Dr. Estevan:

I'm pleased to inform you that your manuscript has been deemed suitable for publication in PLOS ONE. Congratulations! Your manuscript is now with our production department.

If your institution or institutions have a press office, please let them know about your upcoming paper now to help maximize its impact. If they'll be preparing press materials, please inform our press team within the next 48 hours. Your manuscript will remain under strict press embargo until 2 pm Eastern Time on the date of publication. For more information please contact onepress@plos.org.

If we can help with anything else, please email us at plosone@plos.org.

Thank you for submitting your work to PLOS ONE and supporting open access.

Kind regards,

PLOS ONE Editorial Office Staff

on behalf of

Dr. Mohammed Saqr

Academic Editor

PLOS ONE

Associated Data

    This section collects any data citations, data availability statements, or supplementary materials included in this article.

    Supplementary Materials

    Attachment

    Submitted filename: MS.v2-Responses.docx

    Click here for additional data file. (14.1KB, docx)
    Attachment

    Submitted filename: MS.v3-Response to Reviewers.docx

    Click here for additional data file. (12.3KB, docx)

    Data Availability Statement

    Data are available from the project Open Science Framework database (https://osf.io/g7xfw/).

    Articles from PLoS ONE are provided here courtesy of PLOS

    RESOURCES