Study population Sampling design

5 Methodology

2. Methodolog

The GATS is the global standard for systematically monitoring adult tobacco use smoked and smokeless and tracking key tobacco control indicators. The GATS is a nationally representative survey, using a consistent and standard protocol across countries, including Indonesia. The data will assist countries to track technical components of the WHO MPOWER package.

2.1. Study population

The target population for this survey includes all adult men and women in Indonesia aged 15 years and above. This target population includes all people who consider Indonesia to be their usual place of residence, covering 98.4 of the total population in Indonesia. This definition includes those individuals residing in Indonesia even though they may not be considered a citizen of the country. The only adults who were excluded from the study were those individuals visiting Indonesia, e.g. tourists, those who indicated that their primary place of residence was a military base or group quarters, e.g. a dormitory, and those who were institutionalized —including people residing in hospitals, prisons, nursing homes and other such institutions. In addition, eligible respondents could withdraw from the study at any time. They also had a right to refuse to answer any question without providing a reason for their decision.

2.2. Sampling design

The sampling frame used for the GATS Indonesia sample design see Appendix B for details was a census block CB, obtained from the Population Census of Indonesia conducted by BPS-Statistics Indonesia in 2010. The survey applied a four- stage stratified cluster sampling. In the first stage, 100 primary sampling units PSUs 50 in urban areas and 50 in rural areas were selected using the probability proportional to size PPS sampling technique. The PSU consisted of a group of CBs in a subdistrict within the same type of area urbanrural. The next stage was to select three secondary sampling units SSUs, i.e. CBs per selected PSU, also using PPS. After updating the list of population census households in selected CBs, in the third stage, 30 households were selected systematically from the list of updated households. In the final stage, one respondent is randomly selected to participate in the survey. The explicit stratification used at the first stage of selection was based on urban and rural designations of BPS-Statistics Indonesia, as well as on four regions Sumatra, Java –Bali, Kalimantan–Nusa Tenggara, and the eastern part of Indonesia. SSUs were based on CBs created for the 2010 Population Census of Indonesia, which generally comprised 80 –120 households. Following the standard protocol of GATS, the initial target was a representative sample of 8000 non-institutionalized households subject to the applicable non-response and eligibility rates a target sample of 2000 households each in urban, rural, men and women subgroups. After accounting for possible non-response and eligibility rates, it was decided to have an average of 30 households in most of the selected SSUsCBs, resulting in a total sample size of 8994 non-institutionalized households. As per the design, one respondent was randomly selected for the interview from each selected eligible household to participate in the survey. The Indonesian sample design provides cross-sectional estimates for the country as a whole as well as by urbanrural areas and gender.

2.3. Survey questionnaire