4.3 Census, survey and administrative sources

This learning object reviews sources of demographic information appropriate for health care planning. Demographic data are essential for the planning of health care services in order to understand the distribution and characteristics of the population to be served. The health care system itself is not usually able to provide whole-population statistics but relies instead on population data from censuses and administrative sources such as population registers. In some instances, the management of health care may be a primary consideration in the development of a population register. Population surveys can provide detailed information about population characteristics but their sampled nature means that there is rarely sufficiently high coverage of the population in order to produce detailed data for small geographical areas. The presentation demonstrates some of the key differences between these three broad data sources from the perspective of health care planning.
 

 
These types of data source can provide us with important information for the purpose of profiling the population being served by the health care system:

• Demographic data provide information on the size of the overall population and population sub-groups which are the users of specific health services. Information about the prevalence of a specific medical condition or service activity can be combined with these data in order to assess demand and utilization. Demographic modelling, including migration, can be used to build predictive models for future service demand. Population need for health care will vary by demographic characteristics such as gender (e.g. maternity care), age (e.g. childhood vaccinations) and ethnicity (e.g. differing propensities to diabetes between ethnic groups). Censuses and population registers will generally provide the most useful sources of demographic data.
• Socioeconomic data may provide an important additional element in assessing need for health care. In general terms the health of poorer groups will be worse, reflecting a range of factors such as lower levels of education, poorer living and working conditions and poorer diet. A wide range of behavioural factors such as smoking and alcohol consumption which directly affect health are also strongly associated with other socioeconomic variables in many contexts. The exact causal effects on health may not be directly traceable but impacts on population demand for health care can be modelled using multiple deprivation indices, for example. Censuses and population surveys will generally provide the richest sources of socioeconomic data. Censuses will often capture housing and employment conditions while health and lifestyle surveys are useful sources for behavioural characteristics.
• Health-specific information can provide important additional measures for modelling need for health care. Census questions on self-reported health status provide population-level background data while health surveys provide detailed information on health status and behaviour. There is much debate regarding the relative utility of self-reported medical status, as obtained from censuses and surveys, compared to clinical assessments of health status, recorded through contact with health care professionals (for example, Sturgis et al., 2001). While there may be wide variation between levels of ill health reported by individuals, there is undoubtedly much genuine illness which is never presented to the health care system. Some health-specific surveys are administered by qualified medical staff, providing a combination of clinical health assessment with demographic and social background information. There is an extensive international programme of Demographic and Health Surveys (DHS) which seeks to conduct consistent health surveys in developing countries.

Few data sources provide ‘ready-to-use’ measures for the health care planner using GIS, but they can generally be combined or manipulated to provide useful measures. A health survey based on a stratified population sample may establish prevalence rates for particular medical conditions, which need to be applied to a full population dataset from a census or population register in order to produce predictors of the disease burden in the overall population or in specific areas. Geographical referencing is increasingly being taken into consideration in the collection of all the relevant data sources, with linkage either to administrative boundary data in the developed world or GPS data collection in the case of DHS.

 

---

 

---