title: Derivation of indices of socioeconomic status for health services research in Asia.
abstract: BACKGROUND
  Environmental contexts have been shown to predict health behaviours and outcomes either directly or via interaction with individual risk factors. In this paper, we created indexes of socioeconomic disadvantage (SEDI) and socioeconomic advantage (SAI) in Singapore to test the applicability of these concepts in an Asian context. These indices can be used for health service resource allocation, research and advocacy.
  
  
  METHODS
  We used principal component analysis (PCA) to create SEDI and SAI using a structured and iterative process to identify and include influential variables in the final index. Data at the master plan geographical level was obtained from the most recent Singapore census 2010.
  
  
  RESULTS
  The 3 areas with highest SEDI scores were Outram (120.1), followed by Rochor (111.0) and Downtown Core (110.4). The areas with highest SAI scores were Tanglin, River Valley and Newton. The SAI had 89.6% of variation explained by the final model, as compared to 67.1% for SEDI, and we recommend using both indices in any analysis.
  
  
  CONCLUSIONS
  These indices may prove useful for policy-makers to identify spatially varying risk factors, and in turn help identify geographically targeted intervention programs, which can be more cost effective to conduct.
authors: Centre for Quantitative Medicine, Duke-NUS Graduate Medical School, 169857, Singapore; Department of Epidemiology and Preventive Medicine, Monash University, Victoria 2004, Australia.
authors: Arul
authors: A
authors: Earnest
authors: Department of Emergency Medicine, Singapore General Hospital, 169608, Singapore; Health Services & Systems Research, Duke-NUS Graduate Medical School, 169857, Singapore.
authors: Marcus E H
authors: ME
authors: Ong
authors: Department of Emergency Medicine, Singapore General Hospital, 169608, Singapore.
authors: Nur
authors: N
authors: Shahidah
authors: Health Services & Systems Research, Duke-NUS Graduate Medical School, 169857, Singapore.
authors: Angelique
authors: A
authors: Chan
authors: Saw Swee Hock School of Public Health, National University of Singapore 117549, Singapore.
authors: Win
authors: W
authors: Wah
authors: Department of Rheumatology and Immunology, Singapore General Hospital, 169608, Singapore.
authors: Julian
authors: J
authors: Thumboo
keywords: Asia; Health care utilization; Policy; Principal component analysis; Small area health outcomes; Socio-economic index