Fertility rates in Melbourne - where are people having babies?

There's little doubt that Australia is currently experiencing rapid rates of population growth, but much of the focus has been on immigration.  However populations grow in two main ways - through net migration and natural increase ie the difference between births and deaths.  In recent years the number of births in Australia has exceeded 300,000 per annum, with the total fertility rate (TFR) remaining somewhat stable.  While these headline figures provide a national perspective, much of the devil is in the spatial details - so to speak.

Fertility rates in Melbourne

In 2016 there were almost 83,000 births registered in Victoria, with a TFR of 1.73.  Greater Melbourne accounted for more than three-quarters of these births - 65,148 with a TFR of 1.66.  However there is a distinct spatial pattern to the TFR, as shown in the map below.  

In general, the lowest TFRs were found in the inner city and surrounds.  The City of Melbourne recorded a very low TFR of just 0.86.  This is not unsurprising given the young age structure, but it also needs to be considered that there is a large number of students residing here, and they tend not to have babies while completing their studies.

The highest TFRs (more than 2.00, generally considered to approximate replacement level) were recorded on the urban fringe, both in the west and south east.  Wyndham City Council recorded the highest TFR of 2.18.  Again, this pattern is not unsurprising as urban fringe areas tend to be home to young couples and families at the childbearing stage of life.

The importance of geographic scale

In recent years the ABS has been releasing births data at the SA2 level, which are smaller than LGAs and often equate to suburbs.  Within an LGA there can be wide variations in the TFR.  This is important with respect to the provision of services for children and youths.  The map below shows the TFR for SA2s in the Cities of Boroondara and Casey - two very different areas with regards fertility.  

The City of Casey overall has a TFR of 2.03, however it varies from 1.52 in the semi-rural SA2 of Narre Warren North to 2.33 in the rapidly developing SA2 of Cranbourne East.  About half the SA2s in the City had a TFR over 2.0, which is well above the Greater Melbourne average.

The TFR in Cranbourne East and surrounding areas are likely to remain high while they undergo their main phase of housing development (the start of the suburb lifecycle) and first home buyers move in to start their families.  This will increase the demand for schools and other services for young people in the coming decades.  Eventually these suburbs will mature and the TFRs will decline.  Parts of the City of Casey that developed in the 1980s through to the early 2000s are already showing this trend eg Endeavour Hills, Hallam and Berwick.

At the other end of the scale, the City of Boroondara has one of the lowest TFRs in Greater Melbourne (1.33), but there is still some variation within the LGA.  The lowest TFR was recorded in Hawthorn (1.06) and the highest in Ashburton (1.96).  Only Ashburton recorded a TFR above the Greater Melbourne average.  

The City of Boroondara's TFR is more likely to be influenced by housing affordability issues.  This is not a first home buyers area and hence young couples may have their first child in the area, but then move elsewhere as their families expand.  In some SA2s the high student population also influences the TFR - notably Hawthorn, the location of Swinburne University.

A word of caution re small numbers

Although SA2s allow fine-grained geographic analysis, some caution needs to be exercised due to the small populations in some areas.  This is particularly true when the data is examined over time.  Some of these TFRs are calculated on the basis of less than 50 births, so fluctuations in the numbers may provide misleading conclusions about the reasons for this change.  This can occur where new greenfield areas on the urban fringe begin their development phase, with resulting increases in population.  Often the result is a fall in the TFR, sometimes from a very high rate.  For instance Cranbourne East recorded a TFR of 2.61 in 2009, but this was based on 148 births.  This compares with the 2016 TFR of 2.33, based on 662 births.  As the population increases the amount of statistical "noise" in the data diminishes.

Summary

Although the number of registered births are at record levels, the TFR in Victoria and Greater Melbourne is below the national average.  There is a distinct spatial pattern to TFRs across Melbourne, with the urban fringe LGAs recording the highest TFRs.  Conversely, the inner LGAs recorded the lowest TFRs.  

Data at the SA2 level provides finer-grained geographic analysis and confirms that even within an LGA, there is great variability.  This is largely due to differences in the role and function of suburbs, particularly with respect to their age structure and where they sit in the suburb lifecycle.