SimBritain: a spatial microsimulation approach to population dynamics

Abstract

In this paper we present an account of a 3-year research project that is aimed at dynamically simulating urban and regional populations in Britain. In the context of this project we are using data from the 1991 UK Census Small Area Statistics (SAS) and the British Household Panel Survey (BHPS), in order to dynamically simulate the entire population of Britain into 2021 at the small area level. This paper discusses the structure, aims and objectives of SimBritain and presents some preliminary results. Firstly, alternative spatial microsimulation strategies are discussed and their advantages and drawbacks are outlined. Next, the difficulties in calibrating and validating dynamic microsimulation models such as SimBritain are highlighted and ways to tackle these difficulties are explored. The paper then presents some model outputs that highlight the geographical variation of a wide range of socio-economic variables through the 1990s. Moreover, in light of these outputs, the paper discusses the potential of SimBritain for policy analysis.

Using SimBritain to Model the Geographical Impact of National Government Policies

“…The latter is a major national survey of household types and characteristics, which has more detail on socio-economic lifestyles than is contained in the census data alone (see the full list of variables in Appendix A). At the heart of SimBritain lies a relatively simple idea: that by using information from a relatively small number of people (e.g., from a sample or panel survey) and combining it with unrelated information from an extensive large-scale enumeration (such as the decennial Census of Population), it should be possible to add value to the survey microdata set and extrapolate its findings over both space and time (Ballas et al 2005a). Much of the methodology underlying SimBritain is well established.…”

“…To do this, we adopted a deterministic reweighting approach to readjust the given BHPS household weights so that, when all household weights are added up, they fit the small-area constraints. This is described simply in Tables 2-5 (following Ballas et al 2005a). First, Table 2 gives a hypothetical individual BHPS microdata set comprising five individuals who fall within two age categories.…”

“…A more detailed discussion of the SimBritain static modeling process appears in Ballas et al (2005a).…”

“…were carried out and showed equally good model fits on the short-term future. For more calibration of results, see Ballas et al (2005a).…”

“…As Ballas et al (2005a) suggest, in socio-economic terms, some variables are easier to forecast than others. Simulating future aging, births, and deaths is perhaps the most straightforward.…”