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Because space matters: conceptual framework to help distinguish slum from non-slum urban areas
  1. Richard Lilford1,
  2. Catherine Kyobutungi2,
  3. Robert Ndugwa3,
  4. Jo Sartori1,
  5. Samuel I Watson1,
  6. Richard Sliuzas4,
  7. Monika Kuffer4,
  8. Timothy Hofer5,
  9. Joao Porto de Albuquerque6,
  10. Alex Ezeh7
  1. 1Warwick Medical School, University of Warwick Warwick Medical School, Coventry, UK
  2. 2African Population and Health Research Centre, Nairobi, Kenya
  3. 3Global Urban Observatory Unit, United Nations Human Settlements Programme, Nairobi, Kenya
  4. 4Faculty of Geo-Information Science and Earth Observation, Universiteit Twente, Enschede, The Netherlands
  5. 5Institute for Healthcare Policy and Innovation, University of Michigan, Ann Arbor, Michigan, USA
  6. 6Institute for Global Sustainable Development, University of Warwick, Coventry, UK
  7. 7Dornsife School of Public Health, Drexel University, Philadelphia, Pennsylvania, USA
  1. Correspondence to Richard Lilford; r.j.lilford{at}


Despite an estimated one billion people around the world living in slums, most surveys of health and well-being do not distinguish between slum and non-slum urban residents. Identifying people who live in slums is important for research purposes and also to enable policymakers, programme managers, donors and non-governmental organisations to better target investments and services to areas of greatest deprivation. However, there is no consensus on what a slum is let alone how slums can be distinguished from non-slum urban precincts. Nor has attention been given to a more fine-grained classification of urban spaces that might go beyond a simple slum/non-slum dichotomy. The purpose of this paper is to provide a conceptual framework to help tackle the related issues of slum definition and classification of the urban landscape. We discuss:

  • The concept of space as an epidemiological variable that results in ‘neighbourhood effects’.

  • The problems of slum area definition when there is no ‘gold standard’.

  • A long-list of variables from which a selection must be made in defining or classifying urban slum spaces.

  • Methods to combine any set of identified variables in an operational slum area definition.

  • Two basic approaches to spatial slum area definitions—top-down (starting with a predefined area which is then classified according to features present in that area) and bottom-up (defining the areal unit based on its features).

  • Different requirements of a slum area definition according to its intended use.

  • Implications for research and future development.

  • slums
  • urban
  • mapping
  • identification
  • definition

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  • Handling editor Dr Stephanie M Topp

  • Contributors RL conceptualised the paper and wrote the first draft. All authors made material contributions over many iterations.

  • Funding This paper was supported by the National Institute of Health Research (NIHR) Global Health Research Unit on Improving Health in Slums at University of Warwick. The research was commissioned by the National Institute of Health Research using Official Development Assistance (ODA) funding. RL is also supported by the NIHR Collaboration for Leadership in Applied Health Research and Care West Midlands (CLAHRC WM). The views expressed are those of the authors and not necessarily those of the NHS, the NIHR or the Department of Health and Social Care.

  • Competing interests None declared.

  • Patient consent for publication Not required.

  • Provenance and peer review Not commissioned; externally peer reviewed.

  • Data availability statement There is no additional unpublished data from this study.

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