https://doi.org/10.1177/1403494817717557 © Author(s) 2017 Reprints and permissions: sagepub.co.uk/journalsPermissions.nav DOI: 10.1177/1403494817717557 journals.sagepub.com/home/sjp Scandinavian Journal of Public Health, 1–7 Introduction Although non-communicable diseases (NCDs) have become the global leading cause of death, infectious diseases remain a serious problem, especially in devel- oping countries [1]. Indonesia is experiencing a double burden of diseases with both infectious diseases and NCDs, and data are urgently needed to monitor the pattern of health conditions in this region to provide evidence for interventions and to measure their effects. Similar to other developing countries, Indonesia lacks comprehensive population-wide demographic and health data, especially longitudinal data, which measure individual characteristics and link them over Designing and collecting data for a longitudinal study: the Sleman Health and Demographic Surveillance System (HDSS) FATWA S.T. DEWI 1,2 , IFTA CHOIRIYYAH 1,3 , CITRA INDRIYANI 1,3 , ABDUL WAHAB 1,3 , LUTFAN LAZUARDI 1,4 , AGUNG NUGROHO 1 , SUSETYOWATI SUSETYOWATI 1,5 , ROSALIA K. HARISAPUTRA 1,3 , RISALIA SANTI 1 , SEPTI K. LESTARI 1,6 , NAWI NG 6 , MOHAMMAD HAKIMI 1,3 , HARI K. JOSEF 1,7 & ADI UTARINI 1,4 1 Sleman HDSS, Universitas Gadjah Mada, Yogyakarta, Indonesia, 2 Department of Health Behaviour, Environment and Social Medicine, Universitas Gadjah Mada, Yogyakarta, Indonesia, 3 Department of Biostatistics Epidemiology and Population Health, Universitas Gadjah Mada, Yogyakarta, Indonesia, 4 Department of Health Policy and Management, Universitas Gadjah Mada, Yogyakarta, Indonesia, 5 Department of Nutrition, Universitas Gadjah Mada, Yogyakarta, Indonesia, 6 Department of Public Health and Clinical Medicine, Umeå University, Umeå, Sweden, and 7 Department of Community and Family Medicine, Universitas Gadjah Mada, Yogyakarta, Indonesia Abstract Background: This paper describes the methodological considerations of developing an urban Health and Demographic Surveillance System (HDSS), in the Sleman District of Yogyakarta, Indonesia. Methods: 1) The Sleman District was selected because it is mostly an urban area. 2) The minimum sample size was calculated to measure infant mortality as the key variable and resulted in a sample of 4942 households. A two-stage cluster sampling procedure with probability proportionate to size was applied; first, 216 Censuses Blocks (CBs) were selected, and second, 25 households in each CB were selected. 3) A baseline survey was started in 2015, and collected data on demographic and economic characteristics and verbal autopsy (VA); the 2nd cycle collected updated demographic data, VA, type of morbidity (communicable and non-communicable diseases, disability and injury) and health access. 4) The data were collected at a home visit through a Computer-Assisted Personal Interview (CAPI) on a tablet device, and the data were transferred to the server through the Internet. 5) The quality control consisted of spot-checks of 5% of interviews to control for adherence to the protocol, re- checks to ensure the validity of the interview, and computer-based data cleaning. 6) A utilization system was designed for policy-makers (government) and researchers. Results: In total, 5147 households participated in the baseline assessment in 2015, and 4996 households participated in the second cycle in 2016 (97.0% response rate). Conclusions: Development of an urban HDSS is possible and is beneficial in providing data complementary to the existing demographic and health information system at local, national and global levels. Key Words: Sleman HDSS, surveillance, longitudinal study, urban area, feld laboratory, design paper Correspondence: Fatwa S.T. Dewi, Department of Health Behaviour, Environment and Social Medicine, IKM Building 3 rd floor, Farmako Street, North Sekip, Faculty of Medicine, Universitas Gadjah Mada, Yogyakarta, 55281, Indonesia. E-mail: fatwasari@ugm.ac.id Date received 31 March 2017; reviewed 27 May 2017; accepted 31 May 2017 717557SJP 0 0 10.1177/1403494817717557F.S.T. Dewi et al.Designing urban HDSS research-article 2017 STUDY DESIGN ARTICLE