CONSTRUCTING POPULATION ESTIMATES

To calculate age-specific mortality rates, annual estimates of the population at risk are required by sex for each age group 0, 1–4, 5–9… 70–74, 75+, and for each year to 1906 in which deaths were registered. For most of the years between 1850 and 1906, age-specific population estimates do not exist, and so must be calculated, guided by available population information.

Annual population estimates

Official annual population estimates by sex for each colony and State are available, for 31 December for 1788 onward, and for 30 June from 1901 (ABS, 2008a). These estimates are based on the colonial censuses which were undertaken periodically throughout the second half of the nineteenth century, and into the twentieth century (Table 3.4). Mid-year population estimates from 1850 to 1900 were derived from the ABS 31 December estimates.

Table 3.4: Colonial censuses 1844 to 1891, and Commonwealth censuses, 1901 to 1911 New South

Wales Victoria Queensland

Western Australia South Australia Tasmania 26 Feb 1844 26 Feb 1846 31 Dec 1847 10 Oct 1848 1 Jan 1851 1 Mar 1851 1 Mar 1851 26 Apr 1854 31 Mar 1855

1 Mar 1856 1 Mar 1856(a)

29 Mar 1857 31 Mar 1857

31 Dec 1859

1 Apr 1860

7 Apr 1861 7 Apr 1861 7 Apr 1861 7 Apr 1861 7 Apr 1861 7 Apr 1861

1 Jan 1864

26 Mar 1866 2 Mar 1868

7 Feb 1870 31 Mar 1870

2 Apr 1871 2 Apr 1871 2 Apr 1871 2 Apr 1871

26 Mar 1876 1 Ma y 1876

3 Apr 1881 3 Apr 1881 3 Apr 1881 3 Apr 1881 3 Apr 1881 3 Apr 1881

1 Ma y 1886

5 Apr 1891 5 Apr 1891 5 Apr 1891 5 Apr 1891 5 Apr 1891 5 Apr 1891

31 Mar 1901 31 Mar 1901 31 Mar 1901 31 Mar 1901 31 Mar 1901 31 Mar 1901

3 Apr 1911 3 Apr 1911 3 Apr 1911 3 Apr 1911 3 Apr 1911 3 Apr 1911

(a) Part of New South Wales.

Age distributions

The ABS total population estimates have no information on the age distribution of the colonial populations. The colonial censuses do, and provide age for the years in which they were conducted (Caldwell, in Vamplew, 1987; ABS, 2008a; HCCDA, 2014). These provide the information needed for calculations of population age distributions across the entire time period 1850–1906.

The age groups included in published census results usually conform to the required 5-year structure, although non-standard groupings were used in some of the earlier censuses (Table 3.5).

Table 3.5: Age groups published in colonial and Commonwealth census results, 1844 to 1911

Colony

/State Census year Age groups

NSW 1851 0–1, 2–6, 7–13, 14–20, 21–44, 45–59, 60+ 1856 0–1, 2–3, 4–6, 7–13, 14–20, 21–44, 45–59, 60+ Vic 1854, 1857 0–4, 5–9...75–79, 80+ Qld 1856 0–1, 2–3, 4–6, 7–13, 14–20, 21–44, 45–59, 60+ 1864 0, 1–4, 5–9...75–79, 80+ 1868 0–4, 5–9...75–79, 80+ 1876, 1886 0–4, 5–9…55–59, 60–69, 70–79, 80–89, 90–99,100+ WA 1848 0–2, 3–13, 14–59, 60+ 1859 0, 1–4, 5–14, 15–20, 21–29, 30–39…70–79, 80+ SA 1844, 1846, 1851, 1855, 1860 0–1, 2–6, 7–13, 14–20, 21–44, 45–59, 60+ 1866, 1876 0, 1, 2...14, 15–19, 20, 21–24...75–79, 80+ Tas 1847, 1851, 1857 0–1, 2–6, 7–13, 14–20, 21–44, 45–59, 60+ All colonies 1861, 1871, 1881, 1891 0–4, 5–9...75–79, 80+ 1901, 1911 0–4, 5–9...75–79, 80–84, 85+

A number of adjustments were made to the age distributions obtained from published census results, as follows:

 Unspecified ages were redistributed, according to the proportions of known age.

 Some census results were published by single years of age—1891 and 1901 for New South Wales, Western Australia and Tasmania; 1876, 1881, 1891 and 1901 for South Australia—and these show evidence of digit preference. Corrections were made by smoothing, using the Karup-King Newton method for each sex across ages 10–69 years (see Appendix 1). Populations published in the Victorian census reports from 1857 onwards had already undergone smoothing (see for example, Hayter, 1881b, p.35).

 Regression curves were fitted to those censuses with standard age groups, and these were used to derive estimates for each 5-year age group for censuses with non-standard age groups.

 The census estimates by 5-year age groups were linearly interpolated across intercensal years.

 Estimated populations for each 5-year age group were then calculated by pro-rating the ABS total population estimates by the calculated age- specific proportions.

Excluded populations

Information about Aborigines was not collected consistently in colonial censuses. There was considerable variation among colonies in their efforts to count the native population, but also inconsistencies within each colony from one census to the next (Camm, 1988).

Generally, Aboriginal people frequenting the districts settled by Europeans, or employed by colonists, or superintended on reserves were enumerated, but they were included in only some of the published population tabulations. They were often included in New South Wales and Victorian census tables, in some of the Western Australian tables, but were excluded from South Australian tables. In Queensland, they were not counted at all.

Occasionally, estimates of the total number of Aboriginals, including the so- called ‘roving Aborigines’ were published, usually with the qualification that the counts should be considered highly imperfect (Hayter, 1881b, p.16). Again, these estimates were excluded from census tabulations. Considered as a whole, neither Aboriginal deaths nor populations were counted consistently. All that can be said in consequence of the inconsistency in counting Aborigines is that in each colony there will be a small numerator-denominator discrepancy.

The censuses took better account of Chinese persons and other ‘aliens’, with special efforts made to count these populations in Victoria and Queensland, through employing Chinese translators and sub-enumerators. The Registrar- General’s Report for the Queensland census of 1871 specified that

‘Chinamen, Malays, Polynesians and other foreigners, of whatever nation or color, are to be counted; but the native blacks (aboriginals of Australia) are not to be included’ (Scott, 1872).

The Tasmanian total population estimates, based on census results, include counts of both convict and free populations (ABS, 1997). Since only deaths of free persons were included in the abstracts of mortality, with convict deaths registered separately, that colony’s population must be adjusted accordingly to exclude convicts. Newman (2005) provides estimates of the convict population as a proportion of the total Tasmanian population, ranging from 34.4 per cent in 1847 to 3.7 per cent in 1857, and these estimates were used to adjust the Tasmanian population aged 20 years and over.

It is known that nineteenth-century censuses were subject to under-counting (Lee & Lam, 1983; Camm, 1988). Shortfalls occurred in population estimates based on the census, relative to those calculated by Registrar-General’s departments, largely due to the inability to monitor overland migration between the colonies (Hayter, 1893). Although these census undercounts should not affect the ABS total population estimates, they may affect the age distributions of the population if the undercount was not uniform across all age groups.