Northern Ireland

A census of population was carried out in NI in 2001, the only census between 1995 and 2007. This census provided population data, broken down by sex and age, for 582 wards in 26 district councils. Population estimates for each year were available by sex and age at district council level. Annual estimates for the wards were derived from these total annual estimates, using the 2001 census as the basis for the splits by ward. The estimates for each year were then averaged to give an estimated average population by ward for the 1995-2007 period. Over this period the wards had an average population of 2,913, ranging from 784 (Bushmills, Moyle) to 9,654 (Botanic, Belfast) (Table 2.3, Figure 2.1).

Table 2.3 Population distribution of NI wards and RoI EDs

Figure 2.1 Population distribution of NI wards and RoI EDs

NI	RoI

Republic of Ireland

Three censuses were carried out in RoI during the period of this report, in 1996, 2002 and 2006. These censuses provided population data, broken down by sex and age, for 3,422 EDs in 1996 and 2002, and for 3,409 EDs in 2006. Population data were derived from the census small area population statistics (SAPS) files for 1996, 2002 and 2006. Official CSO estimates of the total population split by sex and age (but not by ED) were available for each year from 1995 to 2007. Annual estimates for the EDs were derived from the appropriate census and the CSO total annual estimates–the 1996 census results were used as the basis for the ED populations for 1995, a linear interpolation of the 1996 and 2002 census counts was used for 1997-2001, a linear interpolation of the 2002 and 2006 census counts was used for 2003-2005, and the 2006 census results were used for 2007 estimates. The estimates for each year were then averaged to give an estimated average population by ED for the period 1995-2007.

The average ED population over the period was 1,161; ranging from 62 (Mountstuart, Co. Waterford) to 33,983 (Dundalk Urban, Co. Louth) (Table 2.3, Figure 2.1). Dundalk Urban District comprised a number of EDs in 2006 which were merged for the purposes of this atlas (see below); this merged area was the largest single population unit treated as an ED in RoI. The population of the largest single ED (Blanchardstown-Blakestown) was 23,179.

At each census, the population of a number of EDs was so low that the CSO considered these EDs "confidential", published only total population figures for them, and amalgamated them with one or more neighbouring EDs for the purpose of reporting age-specific population numbers. EDs were considered confidential by the CSO if they included either 15 households or less, or 50 persons or less. There were 12 such confidential EDs in 1996, 19 in 2002 and 32 in 2006. Three of the 2006 confidential EDs had been merged with different EDs in 2002 and so, to create an estimated population for each ED for 1995-2007, any EDs that had been merged during any of these censuses were combined. These are shown in Appendix table A2.1.

The definition of a small number of EDs, and therefore the associated SAPS data, changed between the 1996 and 2002 censuses. These changes consisted of splitting or amalgamation of areas, rather than any movement of boundaries. EDs which had changed in this way were combined for analysis, and the available age and sex distribution similarly combined (Appendix table A2.2). In addition, between 1996 and 2006 there was considerable population growth in a number of towns, many of which consisted of a single ED (urban part), with a surrounding ED (rural part). As the population of these towns increased, they expanded into the rural area, but the ED boundaries remained unchanged. Because of the uncertainty of geocoding of new buildings in these towns, the urban and rural EDs were combined for analysis (Appendix table A2.3). Finally, for the towns of Drogheda, Dundalk and Wexford, population splits were not available for all EDs for all censuses, and the affected EDs were also merged for analysis (Appendix table A2.4). The population of the largest merged ED (Dundalk Urban) was 33,983. This combining of areas gave a final total of 3,355 EDs. 

As the formal definition of “urban” areas in Ireland (RoI and NI) does not include many areas at the periphery of towns and cities, urban and rural populations were distinguished by population density (Table 2.4), based on the estimated average number of inhabitants in 1995-2007. Three categories were created for analysis, with the cut-off points (<1 person/hectare, 1-15 persons/hectare, >15 persons/hectare) chosen to give an approximately equal population in each group.

Table 2.4 Distribution of cancer cases and estimated average population in 1995-2007, and number of EDs and wards, by population density tertiles

* All cancers included in this report.

A range of area-based socio-economic measures is available from the population censuses in NI and RoI. However, the majority of these, particularly those relating to occupation and social class, use different definitions in NI and RoI, and are not directly comparable. Three measures were identified as having a degree of compatibility and have been used for analysis in this report:

1. Unemployment–the proportion of the economically active population aged 16-74 who were unemployed (based upon the definition of unemployment from the International Labour Office (ILO) [1])
2. Educational attainment–the proportion of people aged 16-74 who had a university degree. Academic qualifications which were equivalent to a university degree were included; however, professional qualifications were not, as this information was not available in NI.
3. Elderly living alone—the proportion of people aged 75 and older who lived alone.

These socio-economic measures had to be changed from those in the RoI cancer atlas (Carsin et al., 2009), as the necessary information was not available from the 2001 NI census.

Wards and EDs were ranked according to increasing levels of each of these three variables and were divided into population quintiles, (i.e. each quintile contained as close to 20% of the population as possible). The 20% of the population resident in areas with the lowest percentage of, for instance, unemployment, was assigned to quintile 1 while the 20% resident in areas with the highest percentage was assigned to quintile 5. All measures were based upon data for men and women combined from the censuses of 2001 in NI and 2002 in RoI.

Variations by country

Overall, 40% of the NI 16-74 year old population was economically inactive compared to 34% in RoI. Of the economically active population 7% in NI were unemployed in the 2001 census compared to 8% in the 2002 RoI census (Northern Ireland Statistics and Research Agency, 2003; Central Statistics Office, 2003). While, overall, 20% of the population of the island was resident in each unemployment quintile, 30% of the NI population lived in the areas of highest unemployment, compared to 16% of the RoI population (Table 2.5).

Among 16-74 year olds in RoI, 87% did not have a university degree (or academic equivalent) compared to 84% in NI. 25% of the RoI population lived in the areas with the lowest level of tertiary-level education in Ireland, compared to 10% of the NI population.

41% of the NI population aged 75 years and over lived alone, compared to 31% in RoI. 39% of the NI population lived in areas with the highest level of elderly living alone, compared to 12% of the RoI population.

Table 2.5 Population and number of areas (wards and EDs) included in each area-based socio-economic category

* Annual average of combined 1995-2007 population.

Correlation between socio-economic measures and population density

The three socio-economic measures and population density had varying degrees of correlation. However while the correlation coefficients between several of the measures were statistically significant, none represented a high level of correlation. The highest correlation was a negative association between education and population density (-0.365) (Table 2.6).

Table 2.6 Correlation coefficients (Spearman’s rank) for ward/ED characteristics

Geographic distribution of socio-economic measures and population density

Map 2.3 shows Ireland divided into approximate population density tertiles (<1 person/hectare, 1-15 persons/hectare and >15 persons/hectare). As expected, only geographic areas at the centre of large towns and cities, such as Belfast and Dublin, fell into the highest tertile. The majority of wards/EDs in Ireland had a population density of less than 1 person/hectare.

Map 2.4 shows the percentage unemployed in each ED/ward by quintiles. Areas of highest unemployment were found in north and west Belfast, north-west Ireland (including Donegal, Derry and Strabane), the west of Ireland (including Mayo) and parts of Newry & Mourne and Louth.

Low levels of tertiary-level education (as illustrated in Map 2.5) were found in rural parts of RoI, north and west Belfast, north-east Dublin and south-west Dublin. High levels of tertiary education were found in south Belfast and surrounding areas, central and southern Dublin and surrounding areas, and other urban areas and their environs in RoI, such as parts of Cork, Galway and Limerick.

Areas with high proportions of elderly persons (aged 75 and over) living alone were fairly randomly spread across Ireland, as seen in Map 2.6. The proportion was relatively high in Dublin and Belfast city centres, but low in the surrounding areas.