The survey was distributed online to US adult consumers during the second quarter
of 2011. The participants were recruited through an online sampling service company.
Participants first read an introduction page describing the purpose and the nature
of the survey. Once they agreed to participate voluntarily, participants read the survey
items on a web browser and record the responses on the webpage. A total of
664 responses were collected. 41 responses were discarded during the data cleaning
process due to a large number of missing data and careless responses (e.g. selecting one
number throughout the survey), leaving 623 usable data.