Survey questionnaire development
The survey study was conducted in close collaboration with King Prajadhipok’s Institute (KPI) in Bangkok. The survey questionnaire was carefully elaborated on, translated, and pilot-tested. Data was collected between November 2012 and February 2013. Data collection was coordinated by a local coordinator in each survey location. The survey coordinators were respected academics (in political science/social science) from local universities in each surveyed area. Each survey coordinator worked with an interviewer team consisting of a small group of university students (around 10 per team) with previous experience of survey interviewing for KPI. Data collection in each location began with a training session. In total, 1,200 questionnaires were completed.
 KPI is an independent research organization under the Thai National Assembly with long experience of working with national surveys in Thailand. Among others, they have carried out surveys for the Asia Barometer and World Values Survey.
 The questionnaire is available from the authors upon request.
 The training session consisted of the following modules: presentation of the project, interview techniques in general, interview techniques in relation to sensitive questions, research ethics and anonymity, reading and understanding the questionnaire, explanation of the codes to be used in the questionnaire, KPI requirements for reporting and fieldwork conduct, and finally a session for questions and answers.