Every 5 years, Ireland’s Central Statistical Office (CSO) conducts a national Census. The latest Census happened on 24 April 2016. The data had been captured and processed from July 2016 to February 2017. Census 2016 statistics produced for a range of geographical levels from state, constituencies, counties, electoral division to small areas level. It was published on 20 July 2017.
Census 2016 dictionary can be found in SAPS 2016 Glossary and its geographical boundary can be seen in Census 2016’s map.
Census gives a wide-range of data on different geographical levels, especially on electoral division and small areas. We can view, compare and analyse demographic data such as housing, ethnicity, social class, occupation. In other words, the data contains crucial insights into the dynamic and potential development areas within the Irish housing market.
Section I and II are extracts from the CSO report.
Section III outlines our calculation method for estimating population within a garda catchment area.
I. Electoral Divisions
There are 3,440 Electoral Divisions (EDs) which are the smallest legally defined administrative areas in the State. One ED, St. Mary’s, straddles between Louth – Meath county border and is presented in 2 parts in SAPS tables, one in Louth and the other in Meath. There are 32 EDs with low population, which for reasons of confidentiality have been amalgamated into neighbouring EDs giving a total of 3,409 EDs which appear in the SAPS tables. (Central Statistics Office, 2016)
II. Small Areas
Small Areas are areas of population comprising between 80 and 120 dwellings created by The National Institute of Regional and Spatial Analysis (NIRSA) on behalf of the Ordnance Survey Ireland (OSi) in consultation with CSO. There are 18641 Small Areas. Small Areas were designed as the lowest level of geography for the compilation of statistics in line with data protection and comprise either complete or part of townlands or neighbourhoods. There is a constraint on Small Areas that they must nest within Electoral Division boundaries. Small areas were used as the basis for Enumeration in Census 2016. (Central Statistics Office, 2016)
III. How to estimate population in Garda station’s catchment area using Census 2016
In our crime analysis, https://wheretolive.ie/insight/is-it-safe-to-live-in-areas-with-a-high-presence-of-social-housing/, to ensure a fair comparison between areas with varying population density, we compute the population for the catchment areas covered by each Garda station to give an indication of crime rates per 10,000 head population.
The challenge here is that there is no official population data at the Garda station level. Besides, Garda’s catchment areas rarely fit in a defined census geographical unit. In order to estimate and correlate Census data, we decide to aggregate data from areas having centre of mass, centroid, within a catchment area.
Figure 2 illustrates our approach with an example in which the population for the Shankill station coverage is the green area within the red border of Shankill garda district. This is an approximation rather than an exact calculation as the areas on the borderline have to be assigned to either Shankill, Cabinteely, or Dundrum.
