An evaluation of alternative measures of accessibility for investigating potential ‘deprivation amplification’ in service provision

Studies examining potential social inequities in resource distribution have tended to adopt relatively unsophisticated measures of service supply such as those derived from proximity measures or counts of facilities within given time/distance thresholds. Often such measures do not take into account potential demand for services and the implications this has for understanding socio-spatial patterns in service provision. In this paper, a comparison is made between spatial patterns of accessibility to a range of services by socio-economic gradients for a subset of ‘traditional’ measures of provision with trends revealed by the use of floating catchment area (FCA) methods. Statistical and visualisation tools are employed to examine variations in access scores across deprivation quintiles for all the services included in an accessibility ‘domain’ of a policy-relevant Index of Multiple Deprivation. Findings suggest that, whilst the use of proximity or cumulative opportunity approaches consistently point to greater levels of access in more deprived areas, results from the application of FCA methods point to non-linear trends in the relationship between access and socio-economic patterns of deprivation for some key services. This suggests that the use of measures that account for both potential service demand and distance-decay effects demonstrate patterns that are at odds with those revealed by the use of 'traditional' metrics. We conclude by highlighting prospective implications of using different methodological approaches to measuring spatial patterns of accessibility for understanding socio-economic patterns in service provision, and the broader policy relevance of encapsulating potential service demand within socio-spatial investigations of levels of access.