2.1. Study design
We conducted the online survey from 23 March to 12 April 2020[1] during the COVID-19 pandemic. The cross-sectional survey was completed through an anonymous questionnaire. Our target populations were Chinese univeristy students studying in South Korea (hereby referred to as the International Group) and in Mainland China (hereby referred to as the Mainland Group). We used the same questionnaires for the two groups, and these were written in simplified Chinese characters. The questionnaire was distributed via the Naver Online Survey (Tool) for the International Group and through the Surveystar Online Survey (Tool) for the Mainland Group. Before conducting the survey, we revised and verified the contents of the questionnaire through an online pilot survey and ensured that the statements were appropriate and understandable.
2.2. Data collection
First, the sample size needed for the study was calculated using the G*Power 3.19 program. When calculated based on parameters of the two-sided test, χ2 test, a residual variance of 0.83, α probability = 0.05, and power = 0.95 for F tests and linear multiple regression analysis, the minimum total sample size was estimated to be 356.
Second, during the initial screening of the online questionnaire, a statement regarding the purpose of the research and the confidentiality and privacy of individuals was written on the first page of the survey questionnaire. Participants could only fill in the questionnaire after reading this statement and clicking “AGREE” to confirm their consent. In addition, we stipulated that the main questions in the survey were mandatory questions, which means the participants had to complete all answers before they submitted the online questionnaire. All the measures above resulted in a 100% response rate for our study.
Finally, 461 respondents were collected in this study via snowball sampling, wherein we recruited more respondents among the respondents’ acquaintances. There were 180 responses from Chinese students in South Korea collected from March 23 to April 8, 2020, and 281 responses from Chinese students in mainland China collected from April 2 to 12, 2020. In line with the research aim, which was to survey university students, respondents who answered “Employed,” “Unemployed,” and “Others” to the occupation question were removed, leaving a total of 420 students (171 from the International Group and 249 from the Mainland Group). All respondents expressed their willingness to participate and understood the background and purpose of the study.
2.3. Measurements
After data collection, we compared knowledge, preventive practices, and depression among Chinese university students in South Korea and China. This study used two questionnaires: 1) Questionnaire on COVID-19 and 2) Patient Health Questionnaire-9, which aimed to evaluate the target respondents’ basic demographics characteristics, knowledge about COVID-19, preventive practices, and depressive symptoms. Most questions in the COVID-19 questionnaire were found to have reasonable validity and reliability in Wang’s research on the Chinese general population [15]. Yonsei Global Health Center (YGHC) made changes to Part E (Precaution measures) and Part F (Additional information) according to the specific situation in the two countries. The Patient Health Questionnaire-9 (PHQ-9) was included to the study to provide a baseline for the incidence of depression.
2.4. Description of Variables
2.4.1. General Demographics
In this study, to reflect the demographic characteristics of the respondents, the basic survey asked questions related to the respondents’ sex, age, education level, marital status, family size, whether they had medical insurance, whether they had chronic diseases, whether they had traveled abroad in the past 14 days, and whether they had experienced quarantine. The choices for educational level were “Undergraduate” and “Graduate,” and the choices for marriage status were “Single” and “Married.” In terms of family size, the choices included “1-person family,” “2-person family,” “3~5 persons family,” and “more than 6-member family.” Questions about having medical insurance, chronic illness, having traveled abroad, and having self-quarantined were answerable by either “yes” or “no.” Respondents were also asked about their “self-assessed physical condition,” which was answerable by either “above good” and “below fair.”
2.4.2. Knowledge and perception regarding COVID-19
Understanding and perception of COVID-19 and other topics were evaluated through a self-enumeration questionnaire, which included questions regarding the student’s knowledge on transmission pathway, information satisfaction, sources of related information, confidence about diagnose, degree of concern about this disease, perceived probability, and concern about family members.
2.4.3. Preventive practices of COVID-19
Nine basic preventive practices were incorporated into the questionnaire. The responses to the questions corresponded to the degree to which a measure was practiced on a daily basis (1 = “Never do this” and 5 = “Do this every day”), and the total score indicated how well the preventive practices were performed. Cronbach's alpha coefficient of the preventive practices of the COVID-19 scale was 0.78.
2.4.4. Patient Health Questionnaire-9
Depressive symptoms could be diagnosed based on the nine-item criteria for depression in the Diagnostic and Statistical Manual of Mental Disorders published by the American Psychiatric Association [41]. Each question on the PHQ-9 may have been answered as follows (with their corresponding score):“not at all” (0 points), “several days” (1 point), “more than half the days” (2 points), and “almost every day” (3 points) [42]. Participants were divided into five groups according to the total score: 0–4, 5–9, 10–14, 15–19, 20–27, which corresponded to “minimal or none,” “mild,” “moderate,” “moderately severe,” and “severe” depression, respectively [43]. The higher the score, the more severe the depression.
Depression was assessed according to the score on the PHQ-9. With a sensitivity of 88% and a specificity of 88% for detecting major depressive disorders, a score of 10 has been recommended as the cut-off score for diagnosing depression [44]. Thus, in this study, respondents who scored 10 or more points were classified as “moderate-to-severe,” and respondents who scored less than 10 points were classified as “minimal-to-mild.” Cronbach's alpha coefficient of the scale in this study was 0.89.
2.5. Statistical Analysis
In this study, STATA 15·0 and SPSS 24·0 were used to conduct statistical analysis. The specific analytical methods are as follows:
- First, descriptive statistics, t-test, and Chi-square test were performed to compare each variable between the International Group and Mainland Group.
(2) Second, to explore the determinants of the different depression levels, hierarchical regression was performed.
[1] From WHO, date as of 31 March 2020: China: Total confirmed cases 82,545, total deaths 3314; Korea: Total confirmed cases 9,786, total death 162.