2.3. Data collection procedures
Prior to conducting the study, the researchers received a permission letter from a university administrator in Seoul, Korea, as there is no Institutional Review Board (IRB) for conducting university–based survey. After that, the study protocol received approval from the University of Pittsburgh IRB. No written informed consent was necessary because this study was anon- ymous. Flyers posted in the entrance of the student health service center or public bulletin boards in the university invited potential participants to pick up a study packet in the student health service center. The survey packet included all instruments, an informational letter, and a small gift as a subject incentive ($3). The informational letter detailed the purpose of study, confidentiality of data, right to withdraw, risk/ benefit ratios, and researcher’s contact information. Anonymity of all participants was stressed in the informational letter. A unique identification number was assigned on each survey packet. Potential participants were asked to complete all instruments and return the packet within two weeks, using either a self-addressed envelope or a collection box at the student health service center.